Carnegie Museum of Natural History gratefully acknowledges these individuals and business for providing significant donations of funds, gemstones or jewelry for the Birthstones exhibit in Wertz Gallery: Jack Abraham,
Precious Gem Resources (www.jackabraham.com) The scintillating beauty of gemstones has captured the imagination of men and women since ancient times. Early pagan concepts of astrology and sympathetic magic attributed certain gems with supernatural powers. While some still consider it good luck to wear the stone associated with the month of their birth, most appreciate birthstones for their brilliant beauty. Over the course of centuries, many stones have been designated as birthstones to represent a particular month of the year. As tastes and availability change, different stones are added or subtracted to birthstone lists and some months have been awarded two or more gems. Wertz Gallery uses the official lexicon of birthstones according to the American Gem Trade Association. CLICK
ON A MONTH TO SEE SOME OF THE GEMS DISPLAYED IN WERTZ GALLERY |
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| JANUARY “Garnet” | ||
| “Garnet” is the name for a group of minerals with similar chemical composition and molecular structure. Most people associate garnets with a deep brownish red color, but purple, yellow, gold and green are also common within the garnet minerals. Although gem quality crystals are relatively rare, garnets are common throughout the world wherever igneous and metamorphic rocks are found. The finest gem garnets come from Brazil, Canada, Nigeria, Russia and Tanzania. In the United States, gem quality garnet has been produced from Arizona, California and elsewhere. | ||
 Various colors of “GARNET” |
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| FEBRUARY Amethyst | ||
| Amethyst is the purple variety of quartz. A very common gem, amethyst is found in many localities throughout the world. Amethyst ranges in color from very pale lavender to deep purple. The most desirable color is deep purple with a red-violet tint referred to as “royal” amethyst. The best of this type has historically come from the Siberia region of Russia. Today, most amethyst gemstones come from Brazil, some of which rival the Siberian gems in color. | ||
 QUARTZ variety AMETHYST |
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| MARCH Aquamarine or Bloodstone | ||
Aquamarine is the blue green gem variety of the mineral beryl. Prized for its beauty and durability, aquamarine is a favorite with crystal and jewelry enthusiasts alike. The finest aquamarine gems currently come from Brazil, Russia and Pakistan. Within the United States, gem aquamarine has been found in Colorado and Idaho. Bloodstone is a cryptocrystalline variety of quartz. The name comes from small specks of bright red against a background of deep green. The finest bloodstone has historically come from Russia and India. |
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 BERYL variety AQUAMARINE brooch Photo by Harold and Erica Van Pelt |
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| APRIL Diamond | ||
| Diamonds are best known as brilliant, colorless stones of great beauty and durability. But diamonds also come in a wide range of colors. Yellow and blue are popular and green, pink, violet and black are available. These are known as “colored” or “fancy colored” diamonds. Rich, red diamonds are the most expensive gems in the world. Diamonds have been produced from a number of localities around the world including Africa, India, Russia, Brazil, Colombia and Australia. Most recently, large numbers of fine gems have been produced from Canada. In the United States, gem diamonds have been found in Arkansas, Colorado and Michigan and in glacial deposits throughout the northern states. | ||
 Antique DIAMOND & RUBY necklace |
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| MAY Emerald | ||
| Emerald is the green variety of the mineral beryl. A popular and expensive gem, emerald is very rarely found in high quality crystals. Most fine gem emeralds come from Colombia but, occasionally, Russia, Brazil and North Carolina within the United States have produced significant gems. Tradition dictates that emeralds be cut only in the “emerald cut” style, but modern tastes allow a broader appreciation of styles. | ||
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| JUNE Pearl, Moonstone or Alexandrite | ||
| Pearls are the product of irritated shellfish. Each pearl begins
as a minute grain of sand or other material within the shell of the
animal. It becomes coated by layer upon layer of nacre, composed of
the mineral aragonite, as the hapless crustacean tries to reduce the
irritation caused by its presence. Today, oysters are farmed and seeded
with artificial irritants composed of bits of shell or plastic beads
to ensure a large supply of quality pearls. Pearls produced in this
manner are known as cultured pearls.
Moonstone is a variety of the feldspar mineral albite that displays a flash of color, or chatoyance, when viewed in proper lighting. This effect is the result of crystal twinning on a microscopic scale and is common in the plagioclase feldspars. The color of the flash is usually blue-white with tinges of red, yellow, orange or green, while the color of the stone itself can range from white, the most popular, to gray, brown or orange. Alexandrite, named for a former Czar of Russia, Alexander I, is a special variety of the mineral chrysoberyl. It exhibits a color change from green to red depending upon the type of light it is viewed in. Historically produced from the Ural Mountains in Russia, Brazil currently produces fine gems of this type. |
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  ALBITE variety MOONSTONE Melo PEARL, Vietnam |
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| JULY Ruby | ||
| Ruby is the red gem variety of the mineral corundum. It is second in hardness only to diamond and so rare that top quality gemstones are worth more than white diamonds of similar size. The best rubies come from Myanmar (Burma), Sri Lanka (Ceylon) and Thailand. Ruby has also been produced from the southeastern United States and from Montana, though only rarely and usually of inferior size or quality. | ||
 CORUNDUM variety RUBY |
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| AUGUST Peridot | ||
| Peridot is the yellow-green gem variety of the mineral forsterite, a type of olivine. It is often found in darker volcanic rocks and can be found as glassy green inclusions in the basalts of Hawaii. The “topaz” of the Bible was actually peridot, probably from the ancient deposit on St. John’s Island in the Red Sea. Today, most peridot comes from Myanmar (Burma). Arizona produces fine gemstones, usually less than 1 carat in weight. | ||
 FORSTERITE variety PERIDOT, Egypt Photo by Harold and Erica Van Pelt |
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| SEPTEMBER Sapphire | ||
| Sapphire is a gem variety of the mineral corundum. It occurs in every color except red, which is reserved for the “ruby” variety. The finest sapphires are of a deep blue color but pink, purple, yellow and green are also popular. All colors other than blue are known as “fancy color” sapphires. The finest sapphires come from Myanmar and Sri Lanka. Montana has also produced fine sapphires, but of generally smaller size and less abundance. Most of the stones in this display are from Sri Lanka. | ||
 Fancy color CORUNDUM variety SAPPHIRE Photo by Mike Haritos |
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| OCTOBER Opal or “Tourmaline” | ||
| Opal is chemically like
quartz but with water incorporated into its molecular structure.
Opal is a product of low temperature hydrothermal
activity and is found in volcanic regions like Yellowstone National
Park. It ranges from colorless, white and gray to pastel blue, green
and pink. Only when it exhibits bright “fire” is it valued
as a gemstone. The most valuable opal is black or dark blue-gray with
brilliant red, blue, yellow, green and orange fire. Most precious opal
comes from Australia, Brazil and Mexico. The Virgin Valley in Nevada
produces beautiful black opal but it is susceptible to “crazing”,
or cracking, and is not often used in fine jewelry.
“Tourmaline” is the name for a group of minerals with similar chemical composition and molecular structure. Most tourmaline of the gemstone industry is the mineral elbaite, which occurs in most colors and color combinations, green being the most common. The finest tourmalines come from Brazil, Afghanistan, Pakistan and the United States. Beautiful gemstones and crystals have been produced from Maine and California. |
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| NOVEMBER Topaz or Citrine | ||
| Topaz is best known as a golden-yellow gemstone, but natural colors
include green, pink, red, violet, brown and light blue. Colorless topaz
can be treated with heat and radiation to produce a range of deep blue
and blue-green gems. Topaz is very common, especially in Brazil, and
is found in California, Colorado, Utah and much of New England.
Citrine, the yellow variety of quartz, is often used as a low cost substitute for topaz. Most citrine gemstones result from the heat treatment of amethyst, the purple variety of quartz. |
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 QUARTZ variety CITRINE |
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| DECEMBER Turquoise, Zircon or Tanzanite | ||
| Sky blue turquoise has been highly valued since ancient times. Persia,
Egypt, Tibet and others valued this easily workable stone for jewelry
and amulets. In the United States, turquoise is usually identified
with a southwestern or Indian motif. Much of the turquoise on the market
today is enhanced to one extent or another. Unaltered top quality turquoise
is still a gem to be treasured.
Zircon comes in every color and its high brilliance exceeds even that of diamond. It is common in igneous and metamorphic deposits, although gem quality stones are not common. The best gemstones are currently mined in Thailand and Sri Lanka (Ceylon). Tanzanite is the newest member of the birthstone family. Its deep blue-violet color is the result of heating (naturally or otherwise) of green zoisite. It is found only in Tanzania. |
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