Jewelry glossary
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The baguette cut is a special type of gemstone cut. It’s form is a narrow rectangular with a distinct, elongated table around which two rows of elongated facets are arranged in steps. This shape was developed in 1925 and initially used only for diamonds, then also used on other stones in ensuing years. The baguette cut is particularly suitable for transparent stones.
The bayonet clasp is a secure and innovative closure for colliers. A clasp, which often serves as an ornamental centerpiece, has small holes with hinges on two of its sides. These holes accept posts which are attached to each end of the collier. The posts are inserted into the holes, then given a twist to lock them into place. This principle makes it possible to wear the same clasp with different colliers, or to ornament one collier with any of several different centerpieces.
Not every oyster produces a perfectly spherical cultivated pearl. Just the opposite: most pearls fail to develop into flawless spheres. When they grow in various directions and unusual shapes, they’re called “baroque” or “off-shape” pearls. Depending upon their specific shape, some of these pearls can be very much in demand because they can be made into unique pieces of jewelry.
The word “beryl” is used to describe a group of minerals whose members can occur in a variety of colors. If a beryl is green, it’s called an emerald. If it’s blue, it’s known as an aquamarine. The family also includes the gold beryl, which is yellow in color, the heliodor, which has a greenish-yellow hue, and the morganite, which is pink. Other color variations are known as “noble beryl.” During the Middle Ages, aquamarines were finely polished and set into the viewing windows of reliquaries, where they served as lenses to magnify the contents of the container. This practice led to the use of beryl as a visual aid in the 14th century. The German word for spectacles derives from the word “beryl.”
Bicolor is the term used for a combination of two shades of gold. The combination of yellow gold and white gold, which creates beautiful plays of color and design accents, is a particularly common bicolor. Other tones, e.g. red gold and white gold, can also be combined.
The French word “bouton” means “button.” A bouton pearl is shaped like a button, i.e. it’s round and somewhat flattened. Pearl-bearing oysters doesn’t necessarily produce perfectly spherical pearls. Much more frequently, oysters yield pearls which are oval or irregularly shaped. The latter are known as “Baroque pearls.” In addition to the classical spherical shape, pearls in other symmetrical shapes (e.g. bouton pearls) are also avidly sought.
When a diamond is cut with the brilliant cut, it is referred to as a “brilliant.” The brilliant cut was invented in 1910 as a further development of the old cut. The brilliant cut is considered to be the perfect cut for diamonds because it optimally shows off their inherent fire, luminosity, and radiance. The proportions of a brilliant are precisely defined. Viewed from the side, a brilliant looks like two octagonal pyramids placed one opposite the other. Viewed from above, the stone appears round. The upper side has at least 32 facets which are arranged at precisely defined angles around the table. The lower part has at least 24 facets. The word “brilliant” may only be used for round diamonds that have been given the brilliant cut.
The word “brilliance” is derived from the French verb “briller,” which means “to shine.” Brilliance describes the luminosity of a gemstone, i.e. the overall effects of the reflected light emerging from the surface of the stone. Brilliance depends upon the reflection of incident light, which, in turn, depends upon the refractive index of the stone and the texture of the stone’s surface, but is independent of the stone’s color. The higher the refraction, the stronger the gleam. Diamonds are cut with the goal of achieving the ideal state of complete and total upward reflection of all incident light.
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As long ago as classical antiquity, the belief that a relationship exists between particular gemstones and certain zodiacal signs prompted people to assign particular minerals to each sign of the zodiac. The most common arrangement is given below. The stone associated with each sign is believed to have a positive, strengthening affect on people who were born under its corresponding sign. Aries (March 21–April 20) — red jasper, carneol. Taurus (April 21–May 20) — carneol, rose quartz. Gemini (May 21–June 21) — citrine, tiger-eye. Cancer (June 22–July 22) — chrysoprase, aventurine. Leo (July 23–August 23) — rock crystal, gold quartz. Virgo (August 24–September 23) — citrine, yellow agate. Libra (September 24–October 23) — orange citrine, smoky quartz.
A ball chain consists of numerous ball-shaped elements which have been threaded onto a wire. If the individual balls are made of metal, they are usually hollow. Solid balls of stone, pierced with a hole to accept the wire strand, can also create beautiful effects.
The band is the most important part of a finger-ring. It is the hoop that encircles the finger and thus embodies the fundamental form of the ring. A ring’s band can be flat or rounded. It is usually fitted with a head onto which, for example, the settings for diamonds or colored stones can be affixed.
The braided chain derives its name from its characteristic appearance. These chains look like meticulously coifed braids of hair. Their individual elements intermesh alternately and very closely, thus creating a symmetrical appearance.
The cable chain and the curb link chain are two of the most classical chain forms. Characteristic of the curb chain are the oval links, which are alternately arranged in horizontal and vertical orientation. The cable chain is one of the strongest types of chains. It serves as the basic form for many variations: for example, the outer surfaces of the individual links can be flattened (flat cable chain) or slightly rounded (round cable chain).
The cabochon cut numbers among the so-called “smooth cuts” in which the smooth surface of the stone is not subdivided into facets. Also known as the “mugel cut,” the cabochon is the oldest known cut for gems. Connoisseurs differentiate between ball-shaped cabochons, which resemble a prone hemisphere in side view, and conical cabochons, which rise steeply to a rounded point in side view.
The word “carat” is also sometimes spelled with a “K” but is always abbreviated “ct.” The carat has been used since classic antiquity as the unit of weight for jewelry stones and pearls. Carat, as a unit of weight, should not be confused with “carat” as a degree of purity for gold alloys. Both words are derived either from the Greek word “keration” (the fruit of the carob tree) or from the kuara seed of the African coral tree. One metric carat weighs 0.2 grams. Jewelry aficionados are particularly interested in the weight, i.e. the number of carats, of diamonds. A legendary type of diamond is the “one carat”: i.e. a diamond measuring 6.5 mm in diameter and weighing exactly 0.2 grams. A “half carat” measures 5.2 mm in diameter. A “two carat” is 8.2 mm in diameter.
The carré cut, also known as square cut, is a quadratic shape for transparent gemstones. It’s quadratic table is usually surrounded by a terraced border consisting of two rows of facets.
Many years ago, Chinese pearl farmers began cultivating coreless freshwater cultured pearls in oysters that they farmed in the tributaries and canals of the Yangtse river system. Chinese freshwater pearls have an attractive, nearly spherical shape. The largest ones can be as much as 10 mm in diameter. The spectrum of colors ranges from white, rosé and green to intensive red and lilac hues. In the cultivation process, a bit of living tissue which forms mother-of-pearl is grafted into the body of the oyster so that these pearls have no core and consist entirely of nacre.
A “choker” is a collier that clings close to the neck, almost as though it were choking its wearer. A short, close-fitting chain made of links or a neck-hugging collier made of one or more strands of pearls can each be described as a “choker.” All of the pearls in a pearl choker are identical in size.
CIBJO is the international professional confederation of the jewelry industry. Founded in 1926, the organization has been named “Confédération Internationale de la Bijouterie, Joaillerie, Orfèvrerie, Perles et Pierres” since 1961. All major industrial nations are members. Among the CIBJO’s most important tasks is to designate exact names and descriptions for precious stones and pearls. These official designations are listed in the so-called “Blue Book.”
The citrine is a member of the quartz group. Synonyms are “gold topaz,” “Madeira topaz” or “Spanish topaz,” although these citrines only superficially resemble genuine topaz because they share a similar color with that gem. The name “citrine” derives from the lemon-yellow color, although the most avidly coveted citrines are clear, luminous yellow to brownish-red. The citrine is a hard, non-fissile, and comparatively hard-wearing stone. It’s primary sources are Brazil, Madagascar, and the USA.
The term “clarity” (purity) is one of the four quality criteria (the “4 Cs”) according to which the value of a diamond is appraised. Absolutely perfect diamonds, which are entirely free from inclusions, are rare exceptions. The purity of diamonds is judged very strictly and classified according to an internationally accepted evaluative system. The highest grade is “IF” (“internally flawless,” i.e. entirely free from inclusions). The equivalent German term “lupenrein” means “pure under a loupe.” The other grades are as follows. VVS1 to VVS2 means “very very small included” and refers to diamonds with miniscule inclusions that are invisible to the unaided eye.
A “collier de chien” is a close-fitting, broad or multi-strand necklace. It was the most popular piece of jewelry during the 1920s and it played an important role in the fashions of the late 15th and mid 18th centuries. Nowadays the collier de chien form is interpreted in many different ways. Colliers of this sort are also available with pearls, diamonds, or colored stones. The name comes from the French language and literally means “dog’s collar.”
The technical term “color” is one of the four quality criteria (the “4 Cs”) according to which the value of a diamond is appraised. Stones are judged by comparison with color scales. The majority of these scales have 12 quality grades. The highest grade is “very fine white,” which is used to describe diamonds that are absolutely colorless. Diamonds of this quality are identified by the letters “D” and “E” or by the term “river.” “Fine white” diamonds are identified by the letters “F” and “G” or by the phrase “Top Wesselton.” White stones are identified by the letter “H” or by the word “Wesselton.” Most diamonds are delicately tinged with color, often with a slightly yellowish cast.
The Cullinan is the “Star of Africa.” The largest raw diamond ever found was named after Sir Thomas Cullinan, the director of a South African mine where this diamond, which weighed 3,106 carats, was discovered in 1905. Nine important, large diamonds and 96 smaller stones were cut from this one raw diamond. The large diamonds bear consecutive numbers. The largest of the nine, Cullinan I, weighs 530 carats and is the world s largest cut diamond, a distinction which earned it the cognomen “Star of Africa.” It ornaments the scepter of the Queen of England and is kept in the Tower of London.
The term “cut” (polish) describes the most important of the four quality criteria (the “4 Cs”) according to which the value of a diamond is appraised. The cut given to a diamond is of decisive importance in determining its value. Only a perfect cut can bring the diamond to life and allow it to fully display its fiery sparkle. A good cut reflects light from facet to facet, bundles incident light, and ultimately radiates it outwards again from the top of the stone. If the cut is imperfectly executed, light is lost. The highest brilliance is achieved only by a diamond on which all the facets are correctly proportioned and arranged.
The phrase “colored stone” is used for all precious stones except diamonds and agates. On the other hand, colorless precious stones are sometimes included in the category of “colored stones.” The term “colored precious stone” is also frequently used to emphasize their preciousness.
Corals grow in the ocean at depths of 300 meters or less. Soft polyps very slowly build ramified structures by excreting a chalky substance from their disk-like feet. Coral is thus the scaffold of the polyps, which live in tiny indentations in the branches. Jewelry-quality coral, which primarily grows in the Mediterranean Sea and the Pacific Ocean, occurs in a wide variety of red and pink hues. Particularly desirable are the deep red variety, which experts call “oxblood” or “moro” coral, and a powdery pink variety known as “angel’s skin.”
Corundum is essentially colorless. If trace amounts of other elements (primarily iron and chrome) are present, corundum can display every color of the rainbow. Colorless corundum is a valuable gemstone. After centuries of confusion in the nomenclature, international convention has now agreed to use the word “ruby” to describe red corundum and to use the word “sapphire” to denominate corundum stones in all other colors. The word “corundum” derives from a language spoken on the Indian subcontinent, in which tongue a similar word meant “hard stone.” This etymology is indeed appropriate because with a hardness of “9” on the Mohs’ scale, corundum is the world’s second-hardest gemstone, exceeded in hardness only by diamond. Corundums are found on every continent.
Cultured pearl is the English equivalent of the term that is most frequently used in Austria and Switzerland to describe cultivated pearls. Pearls are typically cultivated by inserting into a bivalve a kernel (usually a lathe-turned spherule made of natural mussel shell) together with a bit of living tissue that produces mother-of-pearl. The bivalve is returned to the water, where it is continually monitored and regularly cleansed. The implanted tissue continues to produce nacre, with which it covers the kernel. The bivalve requires at least 18 months to produce a cultured pearl.
The curb link chain ranks alongside the cable chain as one of the most classical chain forms. A curb link chain is made by taking a chain with links that are connected in the ordinary manner and then twisting it until the links become deformed. Each individual link then looks as though its upper and lower halves had been twisted in opposite directions. Finally, most curb link chains are then subjected to flattening so that their links acquire the characteristic angular Corners.
The cut is the treatment given to the surface of a colored stone or diamond. A good cut can enable the gem to reveal its inherent beauty, color, and gleam. The lapidary art was probably first practiced in India. Prior to and into the 15th century, the treatment given to gemstones usually consisted solely of polishing their natural crystal or cleavage surfaces. Faceted cuts first became widely known during the course of the 15th century. Colored stones are polished by abrading them with polishing disks made of lead, bronze, copper, or tin. Diamonds can only be cut by other diamonds. The hardness of a diamond varies depending on the particularities of its crystal planes and its several axes. Many of the phases in the work of polishing and cutting colored stones and diamonds cannot be accomplished by machines and must be performed manually.
Many gemstones can be split in one or more directions. The breakage occurs along perfectly flat planes. This attribute is called “cleavage” and depends upon the lattice structure of the crystal. Depending upon how easily a gemstone can be split, one can differentiate between perfect, good, and unclear cleavage. A gemstone that cannot be split at all has “no cleavage.” The cleavage of a precious stone must be taken into account when cutting, polishing, and setting the stone because a slight blow or unduly strong pressure can all too frequently cause a gem to split.
Diamond jewelry (solitaires starting at 0.25 carats, pavé starting at 0.50 carat) from Wempe Jewelers are accompanied by certificates, i.e. documents containing the most important items of information about the pieces. The individually drafted certificates of authenticity that accompany each piece of diamond jewelry from Wempe Jewelers above all certify the quality of the gemstones, which are graded according to internationally recognized criteria (the so-called “4 Cs.”).
The cultivation of pearls was first invented in Japan at the beginning of the 20th century. The original method is still in use today. A kernel, typically a spherule which has been lathe-turned from a seashell, is implanted into an oyster together with living mollusk-tissue that produces mother-of-pearl. The bivalves are then returned to the water and cleansed at regular intervals. Inside the shell, the implanted tissue continues to produce mother-of-pearl, gradually covering the kernel with layer after layer of mother-of-pearl. At least 18 months time is required to produce a pearl in this manner. The resulting pearls are called “cultured pearls” or “cultivated pearls.”
Enamel is pulverized glass that has been melted at a high temperature so that it fuses onto a metal substrate. The raw material for enamel is a colorless vitreous mixture which acquires its various hues from the presence of metal oxides. Enamel powder can be sprinkled dry through a sieve or painted wet onto a substrate applied as a viscous paste consisting of powder, water, and plant-based glue. There are four different kinds of enamel: opaque enamel; transparent enamel; translucent, shimmering “opal” enamel; and painter’s enamel, in which fine opaque colored powder is painted onto and then kiln-fused onto an enamel background.
Emerald cut is the term used to describe an octagonal terraced cut that’s most commonly used on emeralds because this cut best complements the character of the gemstone. The emerald has only moderately high refraction and is comparatively delicate. Furthermore, most emeralds occur in elongated crystalline shapes: the elongated shape of the emerald cut conforms with the natural shape of the gem and thus minimizes the volume of stone which is lost during cutting and polishing. At first glance, the emerald cut appears rectangular. Its octagonal shape is created by beveling the corners. Beveled corners protect the stone against damage during the setting process.
An expertise is a written appraisal drafted by a specialist and stating the value of a piece of jewelry or certifying the quality of a precious stone. The document summarizes the essential items of information about the piece: for example, it specifies the weight (in carats) or the purity (clarity) of a diamond. Upon request and for a fee, Wempe Jewelers will draw up an expertise for its pieces of jewelry. Diamond jewelry from Wempe Jewelers (solitaires starting at 0.25 carats; pavé starting at 0.50 carat) is accompanied by a certificate at the time of its sale. This certificate summarizes the most important items of information about the piece.
The verb “to engrave” is derived from the French word “graver” and describes the act of cutting script or ornamental patterns into metal, glass, or stone surfaces. The beginnings of this extremely old technique can be traced as far back as the Bronze Age. An engraving can be either raised or inset. Nowadays engraving can be executed either manually (by an engraver using a burin or an engraving needle) or by machine. Gemstones can also be engraved, in which case they are known as “intaglios” or “cameos.” Wempe Jewelers can individualize a piece of jewelry by engraving it with the initials of its owner.
Emerald is the name given to the most precious stone in the beryl group. The English word “emerald” is derived from the Greek word “smaragdos,” which means “green stone.” Most emeralds are permeated by hairline fissures and inclusions. Perfect gemstones with a rich, dark green color are rarities and are more valuable than comparably sized diamonds. The most beautiful specimens come from Colombia and typically have colorless inclusions. The beautiful green color is cloudier in emeralds from nearly all other sources elsewhere in the world. This cloudiness, however, is no longer regarded as a shortcoming and is known as “jardin.” Emeralds are frequently cut and polished in the so-called terrace cut or emerald cut.
A facet is a planar lateral surface that has been cut or polished on a three-dimensional stone or metal body. Facets enhance the visual effect of a faceted gem. Faceted cuts consist of a large number of small planar surfaces. This method of processing precious stones has been commonly practiced since the 15th century.
Diamonds occur in every color of the rainbow. The most common hues are yellowish, and such stones are appraised together with colorless (so-called “white”) diamonds. Other colors such as green, blue, rosé and red are rarer and are collectively described as “fancy colors.” The most frequent fancy colors are brownish hues and black. Rarer and more precious fancy colors include various nuances of rosé, red, green, and blue.
There are no limits to lapidaries’ imaginations when it comes to the diversity of cuts that can be given to precious stones. Stars, teardrops, triangles, buds — an endless variety of shapes have been devised, many of which are new interpretations of well-known forms. Collectively known as “fantasy” or “designer” cuts, they are used in the design of diamonds and colored stones. Many of these cuts have their own specific names, although many of these names are known only by a few specialists.
As its name implies, this gem is truly born in flame. Fire opals are primarily found in hollow cavities and fissures in mountains of volcanic origin. The name is also due to the stone’s intensive orange color, which gleams in nuances ranging from yellow to red. Though it belongs to the opal group, fire opal is not opalescent (i.e. it has no rainbow-colored shimmer). Most fire opals are milky and cloudy. Only the most precious specimens are clear and transparent. Fire opals can be cut into a facetted shape, which is an unusual form for cut opals. The stone, however, is inherently delicate. The most important deposits are found in Mexico.
Freshwater cultured pearls are very popular nowadays. Formerly small and irregular in shape, recent advances in cultivation have made it possible to attain freshwater cultured pearls which are up to 10 mm in diameter and nearly spherical in shape. This variety of pearl is particularly attractive because of the diversity of colors in which it occurs. The spectrum ranges from white, rosé and green to intensive shades of red and lilac. To cultivate these pearls, no lifeless kernel is inserted into the bivalve: nothing is inserted except a small piece of living tissue which produces mother-of-pearl. As a result, freshwater pearls have no central kernel and consist entirely of mother-of-pearl. Freshwater cultured pearls are currently imported almost exclusively from China, whence their alternate name: “China pearls.”
The frame setting is like a picture frame that surrounds and firmly holds a stone. The metal is wrapped in a thin strip all the way around the stone. The closely fitting upper edge is pressed slightly over the edge of the stone, thus securely holding the gem in its desired position.
Gemstones are nonmetallic materials characterized by the beauty and transparency of their colors, by their hardness, and/or by their rarity. In the past, it was common practice to distinguish between gemstones (which are especially clear and hard) and semiprecious stones (which are nontransparent, less resistant, and less valuable). This distinction, however, makes little sense, so the terms “gemstone” and “jewelry stone” have become more common in modern usage. The weight of a gemstone is measured by the carat (0.2 grams). Gemstones are found in rocks and ores. Transparent gemstones are often cut into faceted shapes (e.g. the “brilliant cut”) to accentuate their inherent play of lights. Translucent and opaque gemstones are usually cut into a smooth domed shape (cabochon).
Gemmology is the science of precious stones. The German language has two cognates for this specialty: “Gemmologie” and “Edelsteinkunde.” Irregardless of the name, the people who are active in this discipline devote themselves to the identification and technical processing of precious stones and to the investigation of methods which can be used to differentiate between natural precious stones on the one hand, and synthetic or imitation stones on the other.
The abbreviation GIA refers to the Gemmological Institute of America, which has its headquarters in Carlsbad, California. The institute is recognized throughout the world as an authority in the fields of gemmology and the grading of diamonds. The GIA is also active in science, research, and teaching. As an educational institution, it offers highly respected gemmological training. Founded in 1931, this noncommercial organization operates branch offices throughout the world. The European headquarters of the GIA are in Vicenza, Italy and London, England.
Gold is one of the first metals used by mankind. Human beings have been fascinated by gold since time immemorial. The metal has a gleaming yellow color, is immune to rust, and is extraordinarily ductile and malleable. The name “gold” derives from the Old High German word “ghel,” which means “shimmering” or “gleaming.” The chemical symbol for gold, “Au,” is derived from the Latin word for this metal, “aurum.” Pure gold is very soft: before it can be used in jewelry, gold must be blended with other, harder metals to create a harder alloy. The admixture of other metals also influences the color of the alloy: the addition, for example, of silver gives gold a greenish cast.
The goldsmith s profession is a traditional career with a very long history. As early as the third millennium BC, the Ancient Egyptians had already begun to cultivate the goldsmith s art: ancient craftsmen artfully worked gold and silver, along with various precious stones and pearls, to create jewelry, utensils, vessels, and other objects. Techniques such as hammering, casting, chasing, punching, engraving, granulation, and enameling have been practiced since ancient times. Nowadays, the goldsmith’s profession is an art and craft which requires an apprenticeship of at least three years’ duration.
The grading or evaluation of diamonds is known as “graduation.” The appraisal is conducted in accordance with internationally recognized, objective criteria. Based on these criteria, diamonds are graded according to their color, clarity (purity), cut, and carats (weight). These four criteria are summarized under the abbreviation “the 4 Cs.”
Garnet is a collective appellation that’s used to describe more than ten jewelry stones which share a similar crystalline structure. The word “garnet” is typically associated with a red stone, but this is only true for the two most common members of the garnet group: the “carbuncle stones” pyrope and almandine. Like their relatives (e.g. green tsavorite and brown to yellow hessonite), these gems have good hardness and high refraction. Garnets are found on every continent.
Pearls are natural products. Although human beings have learned to cultivate pearls and thus to intervene in this natural process, the genesis of a pearl is still subject to the whims of Mother Nature. Cultured pearls grow inside bivalves which are cultivated in underwater “farms.” Alternations in water temperature and natural variations in the concentration of nutrients in the water influence the bivalves’ production of mother-of-pearl, which is the material that accumulates layer by layer to create a pearl. The serial accumulation of these layers often leads to the formation of the ridges or rings which distinguish a genuine pearl and which are regarded as marks of its natural growth.
Inclusions in precious stones are like Mother Nature’s fingerprints. Scarcely any precious stones are entirely free from inclusions. Most gems contain embedded foreign bodies or exhibit disruptions in their crystal structure. The inclusions can be material of the same sort (e.g. a diamond inclusion within a diamond) or of another sort (e.g. zircon in sapphire). The term “inclusion” is also used to describe cracks, hairline fissures, or hollow spaces which may be filled with liquid or gas. Inclusions can detract from the color and appearance of a stone, but many inclusions are not visible to the eye. More recently, inclusions have been recognized as a decorative element because they can cause exquisite plays of light (e.g. cat's eyes and stars). Some inclusions are so typical of a particular mineral that they can be used as proof of the stone’s authenticity.
Internally Flawless is a grade of quality for diamonds and describes a stone’s degree of clarity. This criterion is very strictly evaluated and classified according to an internationally recognized evaluative system. “Internally flawless” is the highest grade in this system and is abbreviated “IF.” Stones of this grade have no inclusions whatsoever. A diamond is only considered to be “internally flawless” if an expert’s eye can detect no inclusions whatsoever under tenfold magnification. Such perfect diamonds are rare exceptions.
Jardin is a technical term that relates to emerald. This noble gem from the beryl group is usually cloudy due to inclusions or hairline fractures. These imperfections are acceptable as long as they don’t detract from the stone’s lovely green color. In such cases, the lively play of colors caused by the inclusions is described as “jardin” — the French word for “garden” — and is regarded as proof of the genuineness of the stone. In no other variety of gemstone are flawed specimens so frequent and perfect specimens so rare.
This phrase is a general term for all ornamental stones and stone-like materials. The term is sometimes applied only to less valuable or nontransparent stones, but in most cases the phrase “jewelry stone” is used as a synonym for the phrase ”precious stone.” There is no clear distinction between the two terms nor any rigorously defined meaning for the phrase “jewelry stone.”
When spelled with a “c,” the word “carat” refers to the units used to measure the weight of jewelry stones. When spelled with a “k,” the word “karat” is a qualitative designation used to describe the fineness of a metal. Every jewelry metal is an alloy which contains different metals in various amounts. Pure gold, for example, is much too soft to be used for jewelry. For this reason, gold (and certain other precious metals) are typically blended with other metals. The number of carats indicates how much of the precious metal is in the alloy. For example, the phrase “14 karat gold” means that 14 units of pure gold are contained within every 24 units of the alloy.
Random chance plays a role in the cultivation of pearls. Sometimes the oyster ejects the kernel that’s been inserted into it to stimulate pearl production, while simultaneously keeping within its shell the piece of tissue that produces mother-of-pearl. When this occurs, an irregularly shaped pearl (known as a “keshi pearl”) is formed. The smallest such pearls are no larger than a pinhead, whence the name “keshi,” which is the Japanese word for “poppy-seed.” Some keshi pearls, however, can grow as large as 10 mm in diameter. Keshi pearls occur in all species of bivalves that are used for pearl cultivation.
The Kimberley Mine was once an extremely productive diamond mine in South Africa. Diamonds were mined by the open-pit method there between 1871 and 1908. Without the use of machinery, workmen at this mine dug the largest hole ever excavated by human hands. Appropriately named the “Big Hole,” it measures 460 meters in diameter and its shaft is 1,070 meters deep. Today, however, the lower half of the shaft is filled with water. Diamonds weighing a total of 14.5 million carats (nearly three tons) were mined there. The mine was abandoned in 1914 after a brief period of below-ground mining.
The name “Koh-i-Noor” means “Mountain of Light” in Persian and suggests what an extraordinary stone this famous diamond truly is. Like the equally legendary Hope Diamond, the Koh-i-Noor traces its provenance to the mines of India. The Koh-i-Noor was first mentioned in 1304, when it had a round shape and allegedly weighed 108 carats. Other sources claim that it in fact weighed 186 carats. The gem came into the hands of the Persian conqueror Nadir Shah in 1739. After the country came under British rule, Queen Victoria received the gem in 1850. Reshaped into its present oval form, the diamond now weighs more than 105 carats. It has been set into the crown of the Queen of England and is kept in the Tower of London.
Kunzite, a variety of spodumene, occurs in pale pink and in shades of violet ranging from pale to dark purple with a pinkish veil. Kunzite has a lively, vitreous gleam. This attractive mineral is relatively delicate. Kunzite is extremely fissile. Brazil leads the world as the chief supplier of kunzite.
The linked necklace is a classical and very feminine chain. It consists of round, voluminous elements which are alternately horizontally and vertically linked to one another. The appearance of this type of chain varies depending upon the thickness and size of its individual links.
The opaque gemstone known as “lapis lazuli” is a mixture of various minerals. The chief component is lasurite, which gives this stone its typical, gleaming blue color. Lapis lazuli usually has stripes or spots of other minerals running through it. The coloration of best-quality lapis lazuli is regularly distributed; often, however, lapis lazuli is spotty or striped. The stone was used as a jewelry stone in prehistoric times. Lapis lazuli was ground to a powder and used as a natural, ultramarine blue pigment during the Middle Ages. Lapis lazuli is moderately hard. The stone is sensitive to warmth, perfume, and cosmetics. Afghanistan is its most important source.
Luster is the most important criterion in the appraisal of a pearl’s value. This technical term describes the reflection of light which refracts on the many strata of aragonite in the mother-of-pearl, thereby creating a gleam that seems to radiate from the interior of the pearl. The reflected light and the gleam should seem as energetic and as deep as possible, two qualities which are associated with a thick layer of mother-of-pearl. A pearl’s value is directly proportional to the intensity of its luster.
Mabé pearls (also known as “cultured blister pearls”) are hemispherical pearls which are particularly suitable for use in brooches and jewelry for the ears. To produce them, several hemispheres of plastic or wax are glued to the interior of an oyster’s shell. As the animal grows, it covers these hemispheres with layers of mother-of-pearl. To harvest the mabé pearls, the mussels are opened and the pearls removed with a milling machine. The hemispherical form is removed, the hollow space is filled up, and the flat back surface is sealed with a mother-of-pearl disk. Most mabé pearls are cultivated inside South Seas mussels of the Pinctada maxima species. The pearls grow to between 10 and 20 mm in size. Depending on the shape of the artificially inserted form, the pearls can be either oval, teardrop-shaped, or heart-shaped.
Majorica pearls are imitation pearls. They are industrially manufactured on the Spanish Balearic island of Mallorca and are considered to be costume jewelry.
Mandarin spessartine is sometimes also known as “mandarin garnet.” This especially beautiful type of spessartine occurs in colors ranging from orange to reddish brown and is a member of the garnet group. Spessartine is named after Spessart, a region in Germany where it was first found. Nowadays the mineral is primarily mined in Burma, Brazil, China, and Kenya. The finest type of spessartine is a variety of mandarin spessartine found only in Namibia.
Marquise is a shape into which gemstones can be cut. The marquise cut is named after the mistress of France’s King Louis XV. She loved this pointed oval shape and was particularly fond of faceted stones cut into a doubly pointed shape. A gemstone cut in this shape is similar to a navette and is likewise grouped under the main heading navette (“little ship”). A marquise diamond has a table and 56 additional facets.
The matrix is the natural stone “womb,” the so-called “mother stone” in which crystals grow and in which they can be found.
Jewelers use the word “memoir” to describe very personal pieces of jewelry: rings with brilliant-cut diamonds that are presented as gifts to commemorate special occasions. The ring’s endless band, which has neither a beginning nor an end, adds even greater meaning to the symbolic character of a memoir. A charming form of memoir ring is a simple and unadorned band in which brilliant-cut diamonds can be successively added as reminders of special events that have occurred in the course of one’s life.
Mineralogy is the branch of science that concerns itself with the investigation of minerals. It can be divided into several subordinate parts: crystallography, i.e. the science of the form, structure, chemical and physical properties of crystals; special mineralogy, which focuses on the description of the minerals according to their genesis, external properties, and distribution; and petrology, i.e. the science of stones, which focuses on the genesis and formation of stones and the transformational processes to which they are subject. The studies of mineral deposits and technical mineralogy complete the spectrum of mineralogical subdivisions.
The Mohs’ scale of hardness is named after it creator, the mineralogist Friedrich Mohs (1773–1839). The Mohs’ scale arranges minerals according to their degree of resistance to mechanical scratching of their surfaces. The scale ranges from one to ten. Each mineral of a given degree of hardness is soft enough to be scratched by a mineral on the next highest level and simultaneously hard enough to scratch a mineral on the preceding lower level. Minerals of hardness 1 are the softest; those of hardness 10 are hardest. Gemstones having a resistance to scratching (Mohs’ hardness) of 1 or 2 are classified as soft; gems in grades 3 to 5 are medium hard; those harder than grade 6 are described as hard. Values for all known minerals and gemstones have been determined on the Mohs’ scale of hardness. The scale is used worldwide to classify the hardness of stones.
The momme is a Japanese unit of weight for cultured pearls. One momme is equal to 3.75 grams or 18.75 carats. This unit of weight is seldom used anymore in the European pearl trade. Nowadays, the weight of a pearl is typically expressed either in grains (one grain equals 0.5 grams) or carats. The latter unit is gaining in popularity.
Morganite is the pale pink to salmon or violet-colored member of the extensive beryl family. Because of its color, this mineral is sometimes also known as “pink beryl.” The name derives from the American collector John Pierpont Morgan. Among other countries, the stone’s principal sources include Afghanistan, Brazil, and China.
Pearls are particularly fascinating today because of their tremendous diversity. Never before have pearls been available in such a wide selection of different colors, forms, and sizes. Each type of pearl has its own spectrum of colors: Tahitian cultured pearls gleam in gray, silver, and black hues, often overlain with a veil of red, blue, or green; freshwater cultured pearls shimmer in white, rosé, and green, and also occur in intense red or lilac hues. When pearls of different colors are strung into a single collier, jewelers describe such necklaces as “multicolor“ or “harlequin” chains. In addition to combining pearls of different colors, such chains also often combine different types of pearls.
Mother-of-pearl is produced by soft-bodied animals, the so-called “mollusks.” The mollusks include marine mussels and snails that have so-called “epithelial cells.” These cells, which produce mother-of-pearl, are responsible for building and growing the mussel’s shell. Mother-of-pearl primarily consists of calcium carbonate, a molecule which contains calcium, carbon, and oxygen. Calcium carbonate occurs in pearls in the form of aragonite, which covers the interior surface of the shell in countless thin, parallel layers or collects around a core like the skins of an onion to produce a pearl. Like a mosaic, each of the paper-thin layers of aragonite consists of countless plate-like aragonite crystals. The cement that connects these crystals to one another is a horn-like, organic substance known as “conchyne.” Mussel shells made of mother-of-pearl have been used in utilitarian decoration and ornamental jewelry for thousands of years.
The navette cut is a narrow, pointed oval shape that resembles a little ship, hence the name. This form’s table is elongated, tapers to twin points, and is surrounded by facets. The shape of the navette cut is similar to that of the marquise cut.
The old cut was invented during the 19th century and is the direct predecessor of the brilliant cut, which has since become the cut that is most frequently used for diamonds today. The old cut is designed with a different number and arrangement of facets than later became common on brilliants. For this reason, diamonds designed in the old cut don’t seem quite as fiery and luminous as brilliants. Various other historical diamond cuts are sometimes found in older jewelry; nowadays, all of them are grouped under the general heading of “diamond old cut stones.”
Olivine is more commonly known as “peridot” in the jewelry world. Olivine received its name because of its pale yellow to olive green color. It numbers among the few precious stones that occur only in one color. Although olivine is not an extremely hard mineral, this stone has been treasured as a precious gem since ancient times. Deposits are found in northern Burma, Australia, and Brazil. Olivine has also been identified as a component of meteorites.
Onyx is the name given to deep black chalcedony, which is a variety of quartz. Onyx is most frequently found as a multi-stratified stone: the material consists of many layers of black substrate and white overlaying layers. Chalcedonies in their natural state can be matte or have a waxy gleam. Stones with varicolored strata can be boiled in sulfuric acid. This treatment gives them a uniformly black appearance.
Orient pearl is the technical term for genuine pearls and/or natural pearls that form inside oysters without human intervention. Cells which produce mother-of-pearl are ordinarily found on the inner surface of the shell, for the growth of which they are responsible. Orient pearls can form when some of these cells stray into the interior of the bivalve. This can occur, for example, when a parasite drills through the shell into the body of the animal, or when a foreign body penetrates between the halves of the shell and injures the animal inside the shell. The mere penetration of a pebble or grain of sand into the interior of the shell is not sufficient to cause the formation of an Orient pearl.
As its name explicitly states, the oval cut is a smooth, oval shape for gems. This cut is derived from the brilliant cut. The chief element of the oval cut is the oval table with its surrounding facets.
The prong setting is a very characteristic setting with slender metal claws that clasp a gemstone like the fingers of a hand. The lightweight and open setting allows the color, fire, and beauty of gem to fully express themselves. Because the gem is held in place by slender pins, the stone itself appears comparatively large and can receive plenty of light. The prong setting evolved from the claw setting in which a gem was held within claws that had been sculpted to resemble the talons of a predatory bird.
Padparaja is the orange to yellow-colored variant of sapphire. Like the more familiar blue sapphire, it too belongs to the corundum group. The name comes from the Singhalese language and means “lotus blossom.” Gemstones with the most avidly sought orange tone are primarily found in Sri Lanka.
Manganese and copper give it its colour. And also its magic. The first neon-blue Paraiba tourmaline was discovered in Brazil in the 1980s. Named after the site of its discovery, it is the rarest and most precious variety of tourmaline. A few additional deposits were afterwards found in Africa. But to the great disappointment of impassioned collectors, this gem remains extraordinarily rare. Stones weighing more than one carat are seldom found.
Pavé, the French word for “paving,” is the technical term that jewelers use to describe flat surfaces of precious metal which have been “paved” with precious stones. Small gems are set closely beside one another to create a flat plane with the least possible amount of metal visible. As a rule, the “paving stones” are of equal size and have been cut and polished in identical shapes. Each stone’s upper facet, its so-called “table,” should lie in precisely the same plane as all the other tables in order to achieve the incandescent, luxurious appearance of fine pavé.
Peacock is the technical term for a particular dark color of Tahitian pearl. This color, which recalls the shimmer of a peacock’s feather, is a dark background hue with an intensive green gleam. This variant of Tahitian pearl ranks among the most avidly sought and most valuable of all cultured pearls.
Peridot is a truly heavenly gemstone. It has been found in meteorites that fell from outer space and landed on Earth. Terrestrial deposits occur at sites in northern Burma, Australia, Brazil, and elsewhere. The favorite gem of the Baroque era, peridot is particularly appealing thanks to its light pistachio or olive-like yellowish-green color. Peridot numbers among the few precious stones that occurs in only one color. The characteristic olive hue prompted mineralogists to also refer to this mineral by the name “olivine.”
Pearls occur in various species of freshwater and saltwater bivalves. They number among mankind’s oldest jewelry materials. In the past, pearls were extraordinarily valuable and were reserved solely for rich and powerful people. Orient pearls occur by random chance and without human intervention. Such pearls are sometimes still found today, but are seldom traded. In the years since the development of pearl cultivation at the beginning of the 20th century, the art and science of creating cultured pearls has been continually refined. More popular today than ever before, pearls are available in many sizes, colors, shapes, and varieties: e.g. as freshwater, Akoya, or South Seas cultured pearls.
Piqué is a technical term used to classify the purity (clarity) of diamonds. Clarity is one of the four quality criteria (the “4 Cs”) according to which the value of a diamond is appraised. Absolutely perfect diamonds, i.e. stones which are entirely free from inclusions, are very rare exceptions. According to an internationally recognized evaluative system, diamonds which clearly reveal inclusions to an unaided eye are assigned to the “Piqué” group, which, in turn, is further subdivided into three subclasses: Piqué I, Piqué II, and Piqué III.
Platinum was not used in jewelry until the end of the 19th century. This metal received its name from Spanish conquistadors in South America, who called it “platina,” which means “little silver” in Spanish. Platinum is the rarest and most precious of all metals. Difficult to mine and laborious to isolate from its ore, platinum is brittle and tough to work with. The alloy that’s most commonly used for jewelry is 950 platinum, which means that there are 950 grams of pure platinum in every 1,000 grams of jewelry metal. The “PT 950” hallmark identifies this quality of platinum.
Polishing refers to the fine treatment given to the surfaces of pieces of jewelry. The goal is to create a smooth and very glossy surface. Polishing can be performed by hand, for example, with a piece of polishing wool, or by machine, usually with a rotating disk made of either leather or wool. Polishing can also be accomplished with the aid of polishing pastes. These preparations enhance the smoothing effect of the polishing. The several phases in the work can be performed either electrochemically, chemically, or in special polishing drums. Pieces of jewelry that show traces of wear can be re-polished by a goldsmith so that they regain their original gleam.
The princess cut is a combination of the brilliant and the emerald cuts. There are several different version of the princess cut. The number of facets can vary depending upon the particular version, and the quadratic shape can be cut into a sharp-cornered or blunted carré.
The term “purity” (“clarity”) is one of the four quality criteria (the “4 C”) according to which the value of a diamond is determined. Absolutely perfect diamonds, i.e. stones which are entirely free from inclusions, are rare exceptions. The purity of diamonds is rigorously appraised and classified according to an internationally recognized evaluative system. The highest grade is “IF” (“internally flawless,” i.e. no inclusions whatsoever). German-speaking jewelers sometimes use the synonymous word “lupenrein,” which means “pure under the loupe,” to refer to “IF” stones. Additional grades are: “very very small inclusions” (VVS1 to VVS2), i.e. with miniscule inclusions that are invisible to the naked eye, and “very small inclusions” (VS1 to VS2).
The word “quartz” describes a large group of minerals that includes many well-known varieties of jewelry stones with identical chemical compositions and similar physical properties. Mineralogists differentiate between quartzes whose crystals are visible with the naked eye (e.g. amethyst, citrine, and rock crystal) and quartzes whose crystals are microscopically small (e.g. agate, chalcedony, and jasper). Quartz occurs in every conceivable color and is used in a variety of technologies. It serves as a raw material for the glass and ceramics industries, and quartz crystals are used as components in optical, electronic, and communications applications.
The phrase “Queen’s Length” has a genuinely regal source: a former Queen of England loved long colliers. Jewelry for the neck with a length of approximately 80 centimeters is named for her. The “Queen’s Collier” is somewhat shorter than the sautoir, which reaches all the way to the waist.
The “radiant” is a special cut for diamonds. This cut is derived from the brilliant cut, but it has more facets than the brilliant cut ordinarily has. Developed by an American named Henry Grossbard, the radiant cut has exactly 70 facets, which give it its characteristic appearance.
Rhodium plating is a process by which the surface of a piece of jewelry is coated with a thin layer of rhodium. Closely related to platinum, rhodium is a very hard metal with a clear, white gleam. Rhodium is used to give a fresher look to the often grayish shimmer of white gold alloys. The layer of rhodium also frequently serves as a protective coating: for example, for items made of silver, because rhodium does not oxidize. Rhodium plating is applied to jewelry after it has been submerged in a galvanic bath.
Rhodolite is actually a pyrope, but has been given a name of its own because of its distinctive rose-red color. Pyrope belongs to the garnet group and was a fashionable stone in the 18th and 19th centuries. The name “rhodolite” is sometimes also used to describe rose-red almandines.
River is an old and now no longer widely used term which was formerly used to appraise the quality of diamonds. “River” is a term used to describe the color of a diamond. “River” is the highest level in the color scale and corresponds to “highly fine white.” In the CIBJO’s internationally recognized color scale, this level of quality is subdivided into “highly fine white +” and “highly fine white” and is labeled with the letters “D” and “E.” The next lowest quality levels are Top Wesselton (“fine white”) and Wesselton (“white”).
Many individual diamonds set closely together in a long row, separate yet flexibly connected with one another, create an impressively luxurious, sparkling bracelet or necklace. That’s how the name of this technique for setting diamonds originated: “Rivière” is the French word for a river or a flowing mass.
Rubellite is a variety of tourmaline. It occurs in colors ranging from pink to red, sometimes with a purplish tinge. Depending upon its hue, a rubellite may also be described as a “red tourmaline” or a “pink tourmaline.”
Ruby received its name because of its color: the Latin word “rubens” means “red.” One of the world’s most valuable precious stones, a ruby can often be much more precious than a diamond of equal size because immaculate rubies are extremely rare. The most avidly sought stones come from the mines of Mogok (Burma) and have a unique color called “dove’s blood” — a special shade of red covered with a breath of blue. Thailand, Sri Lanka, and Tanzania are important sources of rubies. It wasn’t until 1800 that the ruby was recognized as a member of the corundum group. Prior to that date, the word “ruby” was also applied to red spinel and garnet, or else all three were simply called “carbuncle stone.” In the past, the ruby was regarded as a symbol of power, courage, and dignity. During the Middle Ages, it was widely believed that a ruby would darken whenever ill luck or misfortune was imminent.
The rundiste, also frequently written “rondiste,” is part of a gemstone cut. It comprises the encircling girdle between the upper and lower part of the cut. On a brilliant-cut diamond, the facets which are immediately adjacent to this separating belt are referred to as “upper rondiste facets” and “lower rondiste facets.” These are followed by the chief facets and by the table (on the upper side) and the point or culet (on the lower side).
The highly refractive rutile occurs in colors ranging from reddish brown to blood red and black. Although the stone has an almost metallic gleam, it doesn’t play an important role as a jewelry stone. Rutile has a relatively low hardness. This mineral, however, occurs as inclusions in a variety of gemstones. When it occurs as an inclusion, rutile typically appears in needlelike or hair-like shapes which create gorgeous patterns and surprising lighting effects. Rock crystal and smoky quartz sometimes enclose delicate, straw-yellow needles or fibers of rutile known as “Venus’ hair.” Stones containing such inclusions were avidly sought in ancient times.
Precious stones typically embody the focal points of a piece of jewelry. During the long history of the goldsmith’s art, jewelers have devised a variety of settings which hold the gem securely while simultaneously enabling it to optimally reveal its inherent color, light, and fire. Although the crafting of a setting is a task for a goldsmith, the actual insertion of a gem into its setting is performed by a specially trained craftsman known as a “setter.” (See also prong setting and frame setting.)
No two pearls are exactly identical. Even if they come from the same species of bivalve, there can still be tremendous differences in quality. In addition to the size, shape, color, and luster, another important criterion used to determine the value of a pearl is the nature of its surface. Uniform regularity is the most important criterion for the surface: the fewer ridges or indentations, the better the quality of the pearl. Pearls with perfectly immaculate surfaces are uncommonly rare because, after all, a pearl is a natural product.
The Viennese mineralogist Friedrich Mohs (1773–1839) introduced the notion of “scratch hardness” as a way to classify minerals. He defined the concept as the resistance to scratching that a mineral exhibits when one attempts to scratch it with a sharp-edged object. Based on this attribute, Mohs developed his hardness scale, which is today’s most commonly used system for comparing the hardness of gemstones. The Mohs’ scale assigns each mineral to one of ten degrees of hardness. (See also The Mohs’ scale of hardness.)
Santa Maria is the term used to describe a particularly fine quality of aquamarine with a deep and avidly sought blue color. The name comes from the Santa Maria mine in Ceará, Brazil. Brazilian aquamarines with other degrees of quality are known as “Espirito Sant,” “Martha Rocha,” “Fortaleza,” and “Marambaia.” Beautiful aquamarines known as “Santa-Maria-Africana” are found in Mozambique.
This name can lead the unwary astray: the word “sapphire” is derived from the Greek word for “blue.” But sapphires, which belong to the corundum group, occur in every color of the rainbow. Sapphires can be green, yellow, pink, or brown, and each bears the name of its color as a cognomen. When a stone is described simply as a sapphire and without any additional modification, then one is typically referring to the blue variety of sapphire. The red member of the corundum family goes by the name “ruby” and the orange-colored member is called “padparaja.” Sapphires rank among the most avidly sought gems. Stones with a deep, cornflower blue color are especially valuable. The most important sapphire deposits occur in Australia, Burma, Sri Lanka, and Thailand.
Sautoirs are very long necklaces that hang elegantly and sensually all the way to the waist. Measuring as much as 120 centimeters in length, sautoirs were particularly fashionable in the 18th and 19th centuries. Sautoirs are frequently made without clasps and often end in an ornamental pendant or tassel. In the past, the two ends of a sautoir were often pinned with a brooch to one’s belt, to the shoulder of a garment, or to two different positions on a gown or dress. Other versions are fitted with concealed clasps so that the sautoir can also be worn as a multi-strand necklace or bracelet. The sautoir was Coco Chanel’s favorite type of jewelry and is now sometimes also known as the “Chanel chain.”
Like the reptile for which it is named, the snake chain is supple and flexible. It’s surface is nearly closed because the flat links are shaped like scales that are very closely connected yet nonetheless entirely flexible. Snake chains are particularly well suited for use as chains that bear pendants.
Silver is a white, shiny, readily malleable and ductile metal. It has a number of superlative characteristics: for example, it is the most highly reflective of all metals and the best conductor of heat and electricity. Thanks to these attributes, silver isn’t solely coveted for use in jewelry, but is also frequently used in chemical apparatuses, as well as in medical and electro-technical applications. The chemical symbol for silver is “Ag.” This abbreviation is derived from silver’s Latin name, “argentum.” Pure silver is too soft for most applications, so it is usually alloyed with other metals. The phrase “sterling silver” describes an alloy in which 925 parts of pure silver are contained within every 1,000 parts of the alloy.
The word “solitaire” is derived from the French language, in which it means “solitary,” “alone,” or “eremite.” When used in the jewelry context, the term refers to a piece of jewelry which features a single, usually large diamond as its focal point. The term is often used exclusively to describe a ring in which a solitary, stately diamond is the undisputed focus of attention.
South Seas pearls are the finest and most precious of all pearls. Their size alone, which ranges between 10 and 20 mm in diameter, makes them particularly opulent. Pale South Seas pearls have a thick layer of nacre which may vary in color from white to silver, cream, gold, or even a pale bluish-gray. It is this nacre which gives them their gleaming luster. The largest and most beautiful South Seas pearls come from Australia. Indonesia is also an important producer. South Seas pearls grow inside bivalves of the species Pinctada maxima. The rarest and most costly South Seas pearls are white and almost perfectly spherical.
Mankind imitates nature: a synthetic is a man-made mineral that has been created in a laboratory. Synthetics have the same chemical and physical properties as natural minerals. The first methods for manufacturing artificial stones were developed in the mid 19th century. The most common method is the melting-droplet process in which pulverized raw material is heated until it melts. The droplets falling from the molten material congeal into a pear-shaped body whose interior is identical with a natural crystal. Nowadays there’s scarcely any precious stone which cannot be imitated. Man-made surrogates, however, must bear the additional designation “synthetic” when offered for sale.
The original, natural colors of many precious stones can be altered artificially. Irregular or unattractive nuances of color can be improved by heating the gems to a temperature of several hundred degrees Celsius. The best-known treatment is the thermal processing of amethyst: depending on the duration and temperature of the heat treatment, an amethyst’s color can be changed to yellow (citrine) or green (prasiolite). So-called “firing” can give a sea-blue color to aquamarines which have a naturally greenish tinge and can brighten the hue of originally dark tourmalines. These alterations in color do not look at all artificial and do not harm the gems.
The value of a diamond is determined according to internationally recognized criteria (the so-called “4 C”). The most important criterion is the color, which is defined according to an internationally uniform color scale. This scale is usually subdivided into 12 gradations. The top of the scale is the highly fine white known as “river.” The lowest end of the scale is reserved for the toned colors, which have a more or less intensive yellowish tone and which are known, for example, as “Cape.” This yellowish tone is first readily visible in stones graded “Top Cape” and is further subdivided into various grades that are assigned letters from “M” to “Z.”
Lapidaries use the word “table” to refer to the upper polished surface of a jewelry stone. This planar surface, which creates the impression of depth in the stone, is typically surrounded by numerous facets. In baguette-cut or emerald-cut gems, these facets are arranged like tiny steps. The brilliant and navette cuts have interlocking, triangular, or rhombic facets.
The Tahitian pearl is the dark variant of the South Seas pearl. Above all in French Polynesia, Tahitian pearls have been cultivated since the 1960s inside the black-lipped pearl-bearing bivalve Pinctada margaritifera. These pearls reach impressive sizes between 8 and 12 mm, and may occasionally even exceed 15 mm in diameter. Their rich luster gleams in shades of gray, silver, and black, and is sometimes covered with a breath of shimmering red, blue, or green. The most avidly sought hue is called “peacock,” which has a dark greenish shimmer similar to the showy feathers of the bird for which it is named.
Jewelry began as functional objects: i.e. as amulets or talismans. In the past, people wore particular gemstones or symbols to protect themselves from evil or to attract good fortune. In the course of history, jewelry gradually lost much of its original symbolic function and was reduced to playing an exclusively ornamental role. Nonetheless, pieces of jewelry crafted in the shape of particular symbols often play more than merely an ornamental role. The heart, for example, is universally understood as an emblem of love. Cruciform jewelry is often worn as a protective amulet. The trend towards charm bracelets with their many little good luck charms is a “charming” expression of this preference.
Tanzanite is a relatively young beauty, but it isn’t a new mineral. First discovered in 1967, tanzanite is a specially colored variety of zoisite and has thus far been found only in Tanzania. The stone’s appeal derives from its usually immaculate transparency and intensive blue color, which can sometimes verge towards violet. Some tanzanites are bicolor and covered with a purplish tinge.
The name “topaz” was not uniformly applied in the past, when it was used to refer to all yellow, golden brown, and sometimes also green gems. Nowadays topaz is sometimes also called “precious topaz” and designates a group of gemstones whose members occur in many different colors. Most of the colors are pale or pastel, and their hues range from yellow to blue and from green to red and violet. The most valuable topazes have colors ranging from pink to reddish orange. Topaz most commonly occurs as a yellow stone, which sometimes causes it to be mistaken for citrine. Topaz, however, is harder and more refractive than citrine. The only weakness in topaz is its easy cleavage. Brazil is the most important source of topaz.
No longer in widespread use, the phrase “Top Wesselton” describes a particular color of diamond. Second only to river, Top Wesselton is the second-highest grade of a diamond’s color and describes a “fine white.” In the CIBJO’s international color scale, this level of quality is subdivided into “fine white +” and “fine white” and given the letters “F” and “G.”
Transparency refers to the degree to which a gem allows light to pass through it. A gem can be transparent, translucent, or opaque. Transparency is an important factor in determining the value of a gem. Inclusions or cracks detract from a stone’s transparency, which is subdivided into several degrees. Specialists describe a gem as “transparent” when incident light is reflected unhindered, as “moderately transparent” when light is reflected with less intensity, and as “opaque” when light is completely absorbed.
The terrace cut is one of the facetted cuts. It has a rectangular shape. The rationale for the name becomes apparent when one views this cut from the side: the terraced shape has characteristic “steps” leading upwards to a flat top or “table.” This cut has been further evolved to create the emerald cut, in which the four corners of the rectangle are blunted.
The trilliant is a cut that gives a diamond the shape of a symmetrical triangle. Diamonds cut in this shape are often set alongside colored stones or large diamonds. The “troidia” cut is another triangular cut with three convex sides and, depending on the size of the gem, from 77 to 107 facets.
The teardrop cut is a particularly charming type of cut. As its name states, teardrop-cut gems have been cut and polished into the shape of a droplet. The table too is shaped like a teardrop, and this shape is further emphasized by the design of the surrounding facets. The names “briolett,” “poire” (French for “pear”) and “pampel” are also used to describe stones which have been cut into teardrop shape.
No other mineral has been revered as a holy stone and talisman by so many cultures around the world. Mankind has perennially been fascinated by turquoise and its opaque, sky-blue to apple-green color. The name, which means “Turkish stone,” recalls the days when turquoise reached Europe along trade routes that passed through Turkey. The most avidly sought color, a clear sky blue, is also the rarest hue. Most turquoises have dark veins of other minerals running through them. The best-quality turquoise comes from Iran. This mineral isn’t especially hard and is slightly porous. The latter attribute makes it sensitive to perspiration, cosmetics, and perfume.
The tourmaline group includes stones which occur in a wide variety of colors. Some color variants have names of their own, e.g. tourmalines whose colors range from pink to red are known as “rubellite.” Black tourmalines are also known as “schörl.” Green ones are termed “verdelite.” Blue tourmalines are called “indigolite.” Monochrome tourmalines are quite rare. It is much more common for a tourmaline to exhibit different shades or sometimes even entirely different colors, hence the name: turmali is the Singhalese word for “stone with a mixture of colors.” Brazil is the world’s most important source of tourmaline.
Taper refers to a necklace or bracelet whose volume decreases from the midpoint towards the clasp. A tapering pearl collier, for example, has its largest pearl situated at the midpoint. The diameter of the strung pearls decreases regularly as their distance from the midpoint increases and their nearness to the clasp increases.
The vibrating waves of ultrasound are particularly useful to jewelers because these sound waves can be used to cleanse delicate or difficult-to-reach surfaces. The pieces of jewelry which are to undergo cleansing are immersed in a bath containing a cleaning fluid. Sound waves with frequencies above the limit audible to human ears create vibrations which loosen and remove tarnish or soiling from the treated surfaces.
The Venetian chain, also known as the “Venetian box chain” or “mignon chain,” evolved from the anchor chain. It consists of quadratic elements which are formed from rectangular strips of metal. As is also the case in an Erbskette, the links of a Venetian chain are alternately connected to one another in horizontal and vertical orientation.
The term “Wesselton” is no longer widely used. It describes a particular color of diamond. Wesselton follows river and Top Wesselton as the third-highest grade in the scale of diamond colors. It follows “highly fine white” and “fine white” and corresponds to diamonds whose color is rated as “white.” This quality level is assigned the letter “H” in the CIBJO’s internationally recognized color scale.
Zircon is a mineral that’s full of luminosity and fire. Although its name probably derives from the Persian language and means “golden colored,” zircons in fact occur in many different hues. It’s refraction is nearly as high as that of the diamond, but zircons are very brittle and thus sensitive to pressure and shock. Varieties of zircon include the yellow to reddish brown “hyacinth zircon,” the straw yellow to nearly colorless “jargon zircon,” and the blue “starlin,” which is usually produced by heating other zircons. Zircons are found in Asia, Australia, South America, Africa, and elsewhere. The natural zircon has nothing except a similar-sounding name in common with zirconia, which is a synthetic stone.
Zirconia is the man-made, synthetic stone which best imitates a natural diamond. It’s physical properties are similar to those of its noble model, and zirconia achieves very good visual effects. Synonyms are “fianite,” “phianite,” and “CSZ” (cubic stabilized zirconium oxide). Zirconias have been manufactured in a wide range of sizes and shapes since 1977. Some zirconias have even been made with artificial inclusions. Zirconia shouldn’t be confused with zircon, which is a naturally occurring mineral.