Precious Gemstones
Everything Has beauty but not everyone can see it
Grading and valuing diamonds
In general, intensely colored natural diamonds command very high prices. However “colorless” diamonds, because they have a generally higher value than most “colored” stones, are graded by a more complex system. A single change in grade can result in a large difference in value. To avoid the large value changes between the grades that would occur if there were only a few grades, there are numerous grades based on each of the four “Cs”, thus keeping the changes in value relatively small. The grades and their determinates are those of the Gemological Insitute of America (GIA).
With exceptional beauty, luster, and sparkle, the diamond is the most iconic of all precious stones and highly prized in jewelry all over the world. However, this is only one of its uses. Industrial diamond is a vital component in oil drilling, specialized scalpels, tool manufacturing, and many other industries, all of which use the supreme hardness of diamonds for cutting tools and abrasive powders. There is no firm boundary between gem-grade and industrial-grade diamonds – around 80 percent of the diamonds mined each year are unsuitable for gemstone wear, and find other uses in industry. However, very small or low-grade stones can be polished into gemstones rather than being used in industry.
Discovering Diamonds (History)
For over 2000 years, diamonds were found only as crystals in river gravels, and, until 1725, India was the major source. As Indian production waned, diamonds were discovered in Brazil, and in 1867 they were found in gravels near the Orange River in the Kimberley region of South Africa. Further exploration there revealed volcanic pipes of a previously unknown rock type containing diamonds; this was named kimberlite and was recognized as the diamond source rock. Its discovery formed the basis of the modern diamond industry. Many similar pipes have since been found in other African countries, Siberia, Australia, and more recently in Canada, China and the US.
The Orange (A Natural Rarity)
Orange-colored fancy diamonds are noted for their rarity, and mostly occur only in smaller sizes. As a result, this gemstone caused a stir when it was put up for sale. At the time of its auction in 2013, The Orange was claimed to be the largest fancy vivid orange diamond in the world – estimated to be 14.82 carats. Its size, beauty, and rarity were reflected in its price, and it was sold by Christie’s auctioneers in Geneva for over $35 million.
Diamond Enhancement
“Fancy” (colored) diamonds demand high prices if the colors are definite and intense. Reds, violets, and blues bring the highest prices. They are not always what they seem. Today, a number of processes exist to change the color of white diamonds, from irradiation to flooding them with gases that are absorbed and produce color change. Other enhancements include laser drilling to remove inclusions and the application of sealants to fill cracks. Buyers should always purchase diamonds certified by a legitimate testing agency.
July’s birthstone, ruby takes its name from Latin ruber, or red. Rarer than diamonds in large sizes, rubies are, for some, the supreme gemstone, leaving diamonds in the dust. Ancient Romans believed that rubies excited the passions and guarded one’s wealth and rank. A kernel of truth lies behind the many stories about rubies glowing in the dark: As modern gemologists know, certain stones are demonstrably fluorescent.
October’s birthstone, opal is a magical, almost otherworldly gem. Once thought to include the colors of all precious stones, opals possess uncanny powers for a variety of cultures. Dangled as a hypnotic talisman or powdered into a compound to instill invisibility, opals, in one way or another, were and are bewitching and mysterious.
Known since antiquity, opal derives its name from the Latin word “opalus,” meaning “precious stone”. Opal falls into two categories: precious and common. The former displays highly prized rainbow iridescence with a white to dark body color, while the latter has a strong, attractive body color and no iridescence. Both kinds consist of hardened silica gel, and usually contain 5-10 percent water in submicroscopic pores. Precious opal consists of a regular arrangement of tiny, transparent, silica spheres, and its color play occurs when the spheres are regularly arranged and of the correct size, causing the diffraction of light and its consequent breakup into the colors of the spectrum: the actual colors that appear depend on the size of the spheres. Opal is deposited at low temperatures from silica-bearing waters, usually in sedimentary rocks. In ancient times, the primary source was present-day Slovakia; more recently, Australia was the main producer, and is also the source of fossil bones and seashells that have been replaced by precious opal. Ethiopia is now the main source of the gem opal.
One of the most desirable gemstones, emeralds are the rich green variety of beryl, the mineral found in igneous, metamorphic, and sedimentary rocks. Most emeralds have numerous inclusions and internal flaws, and these imperfections are unique to each stone. For jewelry, the brittle gem is usually faceted in its signature emerald cut. This is a step, or trap, cut, which combines a rectangular shape with shortened corner facets, maximizing the emerald’s distinctive green color, and protecting it from external damage and internal stress.
Ancient history records Emerald mines near the Red Sea called “Cleopatra’s Mines,” where Pharaohs sent workers to gather gems between 3000 and 1500 B.C. History also speaks of the Maharajas of India, whose treasure vaults were filled with emeralds – often believed to bring luck and health. The green of emerald is representative of life and springtime.
The most coveted quartz, Amethyst is celebrated for its calming, deep violet hue. From a Greek word meaning “not drunk,” amethyst was also the name of a legendary maiden in Greek Mythology.
According to myth, Amethyst was created by Bacchus, the Greek God of intoxication, wine, and grapes. He was pursuing a woman, Amethyste, who refused his affections and prayed to the gods to remain chaste. The goddess Diana responded, transforming Amethyste into a white stone. In shame, Bacchus poured a goblet of wine over the stone as an offering, dyeing its crystals purple.
A green stone that can be translucent and feature cloudy areas of milky white. Tougher than nephrite, jadeite jade was strong enough to be used in the fabrication of ancient weapons.
There are two distinct minerals both called Jade – nephrite and jadeite. They have very different textures: jadeite is made of interlocking, blocky, granular crystals whereas nephrite is fibrous. Nephrite comes only in cream and shades of gree, while jadeite comes in many other colors, and its pure form is white. The most valuable is emerald green, which is colored by chromium and known as Imperial Jade. The name jade comes from the Spanish piedra de hijada, or “loin stone,” named in the belief that it cured kidney ailments.
September’s birthstone, sapphire is most famous as a stunning regal blue gem. The blue sapphire, tinted by titanium and iron, reigns as a unique and potent precious gem. Ancient Romans believed that it guarded one from envy, increased wealth, and protected rulers from harm (Especially poisons).
A stunning and feminine pink stone with the depth and class of its better-known blue siblings, pink sapphire pairs well with other pink, purple, or red gems.
Aquamarine is the essential light blue gem. Meaning “Ocean water,” aquamarine is a close — though less rare – cousin to other beryls like emerald and morganite. A chosen amulet of sailors in antiquity, aquamarine was believed to promote youthful vitality, health, and mental clarity.
Once, it was believed that all yellow gems were Topaz, and that all Topaz was yellow – however, neither statement is true. Some Topaz is yellow, but it can also be colorless, blue, green, sherry, and its most valuable color variation, pink, it is fairly refractive, splitting light into its constituent colors; as a result, colorless Topaz resembles diamond, and has often been mistaken for it. Additionally, some blue topaz is almost indistinguishable from aquamarine. A certain number of gems on the market have been treated by heat and irradiation to change their color.
In a lighter red hue, tinged by varying shades of purple and pink, rhodolite garnet takes its name from the vivid blooms of the mountain rhododendron, which grows in the Appalachian regions where the stone is mined. The words rhodolite and rhododendron both derive from a Greek word meaning “rose”, or “rose-colored”
January’s birthstone, garnet is a beautiful, hardy, and abundant gem with a distinct and desirable color profile. Mozambique garnet, a fiery pyrope, offers the warm, wine-red color that garnets are best known for.
Garnets are generally thought of as red, but they can also be orange, pink, green, black, and honey brown. All species of garnets have similar physical properties and crystal forms, but differ in chemical composition. There are over 15 garnet species, of which six varieties are most commonly used as gems: pyrope, almandite, spessarite, grossularite (includes hessonite and tsavorite), andradite (includes demantoid), and uvarovite. Although they are found in many different colors and compositions, garnets are easily recognized because they are generally found as well-developed crystals with a basic – although sometimes modified – dodecahedral form. The name “garnet” is derived from Latin granatus, from granum(“grain, seed”), possibly a reference to the vivid red seed covers of the pomegranate, which are similar in shape, size, and color to some garnet crystals.
Citrine, which takes its name from the French word “citron,” or lemon, is a golden yellow quartz tinted by traces of iron. Extremely rare in nature, most citrine is created by heating amethyst. Like golden Topaz, for which it was often confused in the past, citrine’s autumnal colors make it a fitting November birthstone.
Flickering between a noble green and a deep red depending on the light, the finest specimens of Alexandrite are among the world’s most rare and coveted gems. Alexandrite was discovered in the Ural Mountains of Russia in 1830, supposedly on the birthday of its namesake, the eventual Czar, Alexander II. The conventional stone for the 45th wedding anniversary, Alexandrite has an impressive reputation despite being relatively new on the scene. To this day, many Russians believe that Alexandrite imparts good luck to the wearer.
The Alexandrite variety of chrysoberyl displays a color change, from greenish to reddish, when seen in different light conditions. Alexandrite appears greenish in daylight, where a full spectrum of light is present, but reddish in incandescent light, because it contains less of the green and blue spectrum. The color change is due to chromium atoms replacing the aluminum in the chrysoberyl structure. This causes intense absorption of light over a narrow range of wavelengths.
Also known as “Black Pearls,” Tahitian Pearls smolder with a rich blend of peacock green, purple, and gray overtones. Found most famously in the crystal blue lagoons of French Polynesia, Tahitian pearls are formed within the pinctada maragaritifera, or “black-lipped,” oyster. Although cultured today, they were harvested until recently by free-diving Polynesian fishermen. A great look for men in a cuff link or tie pin, and a sophisticated choice in earrings or necklaces for women of all ages.
Pearls are natural gems produced by the pearl oyster and the freshwater pearl mussel. Although other kinds of mollusk can produce a “pearl,” these have little value since they are not composed of nacre (the same substance as mother-of-pearl). Nacre is secreted in response to a microscopic irritant in the mollusk’s soft tissue. The concentric rings of nacre around the particle create the particular iridescence of pearls due to the way the overlapping layers diffract light waves. A pearl’s color is described in terms of body color and overtone – the most common body color is white, though it can range widely, and the overtone is the color that seems to appear only on the surface of the pearl.
Natural and man-made
Natural pearls that form in the wild are rare and valuable, and pearl divers have to open hundreds of pearl oysters before chancing on a specimen. Although diving for natural pearls still occurs in Bahrain and Australia, today’s pearls are largely cultured, making them much more affordable: an artificial nucleus, such as a round shell bead, is placed in the oyster or mussel for the nacre to form around. Freshwater pearls are cheaper because the freshwater mussel can produce up to 20 pearls at a time, whereas the smaller saltwater oyster can create just one. Saltwater pearls are differentiated by region: South Sea pearls are more valued due to their size, Tahitian pearls are next for their colors (black among them), with Akoya the least prized, being the most common.
The luminous beauty of South Sea Pearls is the stuff of legend. A uniquely transparent luster and a vivid color palette partially explain their charm and account for their status as the most sought after of pearls.
South Sea Strands
A matched strand of South Sea Pearls provides an easy path to immediate elegance. Long treasured as the most desirable pearls on the planet, South Sea Pearls are magnificent and stunning when displayed alongside their peers.
December’s Birthstone, blue zircon is not, nor has it ever been, cubic zirconia, and your customers should be aware of it. Zircon is a beautiful, brilliant, and unique natural gemstone that has been known since antiquity. Medieval Europeans believed that zircon promoted restful sleep and wealth, and that it dispelled evil spirits. The genius of 19th century gemology, George Frederick Kunz, was enamored of zircon — to the extent that he launched a campaign to rebrand it as “starlight” in recognition of its ethereal beauty.
Some zircon material is 4.4 billion years old, making it the oldest-known mineral on Earth. It is a colorful gem with high refraction and fire. Colorless zircon is known for its luminescence and reflective flashes of multicolored light, and is often used in jewelry as a substitute for diamonds. Vibrant blue zircons are produced by heat-treating the more common brown stones. The mineral sometimes contains traces of uranium and thorium, and this natural radioactivity can disrupt the crystal structure, causing changes to color, density, RI, and double refraction.
Possibly from the Person word “faridat,” meaning gem, peridot is another name for gem-quality olivine. Often mistaken for emeralds in the Middle Ages, peridot adorns some of the most ornate ecclesiastical jewelry, such as the famed Treasury of the three Magi in the Cologne Cathedral in Germany. Peridot is one of a small group of gemstones that appears to exist in only one color. Today, the United States is the leading producer of peridot, with most production coming from the San Carlos Indian Reservation in Arizona.
Louis Comfort Tiffany’s great grandson, Henry B. Platt, famously gave tanzanite its name in 1968, when Tiffany & Co. made a deal to become its main distributor. A Maasai tribesman had discovered the first known tanzanite only a year earlier in the Arusha region of Tanzania, near Mount Kilimanjaro. A deep, luminous blue with hints of violet, tanzanite takes on a more purplish violet hue in artificial light.
Tourmaline refers to a family of borosilicate minerals of variable composition, but all with the same basic crystal structure. There are more than 30 mineral species in the tourmaline group, including elbaite, dravite, and schorl. However, while mineral names are based on chemistry, gemstone names are based on color and take no notice of tourmaline species. These include indicolite (blue), achroite (colorless), and rubellite (pink or red). The crystals generally form pencil-like prisms, with a rounded-triangular cross section, and, unlike the rocks in which they often form, tourmaline minerals are resistant to weathering. As a result, they tend to accumulate in gravel deposits; the origin of the name is the Singhalese word turamali – which means “gem pebbles”
Variety of colors
There is no simple correlation between chemical composition and color. Most gemstone tourmaline material comes from the species elbaite, which is usually green, although it can occur in many other colors. Emerald green is fairly rare and thus valuable; until the 18th century, it was often confused with emerald. The most dramatic tourmalines ar ethe color-zoned gems called “watermelon” tourmaline: when sliced across the crystal, this variety shows a red or pink center surrounded by a rim of green. The deepest color is always seen when looking down the length of the crystal, so it is important to position rough material correctly when cutting gems.
A birthstone for October, pink tourmaline was highly treasured in China, where they were the favorites of empresses and mandarins. Among the many fascinating properties of tourmaline is its piezoelectricity – the ability to convert pressure into a small electric charge. For this reason, the Dutch (Who introduced the stone to Europe) used them to pull ashes out of their pipes, giving them the nickname, aschetrekker, or “ash-puller”>
Well-formed crystals of green tourmaline from northwestern Zambia show a growth pattern reminiscent of trapiche emerald/ruby when sliced perpendicular to the c-axis. In fact, such slices were originally encountered in parcels sold as emerald in Zambia. The trapiche appearance most likely originates from skeletal growth, with the pattern formed by a black carbonaceous substance (mostly graphite) that partially filled growth tubes concentrated in three areas: (1) along the three edges of the trigonal pyramids r {101–1} or r’ {011–1 – }, (2) at the interface between the trigonal pyramids and the prism a {112–0}, and (3) between individual growth sectors of the prism a. Spectroscopic and chemical analyses indicate that the tourmaline is uvite that is colored green by a vanadium-related mechanism. To the authors’ knowledge, this is the first occurrence of trapiche tourmaline.
A staple of Victorian mourning jewelry, smoky quartz is the national gem of Scotland, where it was once produced abundantly from mines in the Cairngorm Mountains. Easily had in large sizes, this dark and brooding quartz is a good choice for a customer looking to make a statement.
A soft, romantic pink beryl, morganite was discovered in Madagascar in the early 1900s. George Frederick Kunz, the eminent mineralogist and Tiffany & Co. vice president, named it to honor his patron J.P. Morgan. As the story goes, he did this because he had previously failed to honor Morgan upon discovery of another precious pink stone, kunzite, which he of course named for himself.