G A R N E T S |::| Mohs' Hardness 7 - 7.5
The garnet family of gems is comprised of a variety of stones which share enough common characteristics so that gemologists group them together as the garnet family. This family of stones is suitable for a wide variety of jewelry applications, and garnets are durable enough to be worn on an everyday basis. Garnets are often found in antique jewelry, and they were frequently used in men's rings from the mid-1800's to the current date.
Colors can range from colorless to a near black deep burgundy, and from bright red to deep green. Rare, green colored demantoid garnets are quite costly, while brownish-red almandine garnets are very affordable. Garnets are found throughout the world, with significant U.S. deposits in Idaho and North Carolina.
A M E T H Y S T |::| Mohs' Hardness 7
Of all the various colors of quartz gemstones, the purple color of amethyst is the most highly prized. Folklore holds that amethyst helps in overcoming homesickness, and when worn, helps in preventing drunkenness.
At the turn of the 20th century, and up through the 1920's, the shade of amethyst most favored in jewelry was a pale lavender shade known as rose of France. In recent times the fashion trend has been to use a deep purple colored gem.
The purple color saturation can, however, become so dense as to make the stone overly dark, causing the stone to lose brilliance. Amethyst is a hard stone, suitable for use in everyday jewelry, and its moderate price adds to its consumer appeal. In the United States the finer stones are mined in Arizona, with better quality foreign sources in Brazil, Africa and Russia.
A Q U A M A R I N E |::| Mohs' Hardness 7.5 - 8
Aquamarine is so named because of its resemblance to the color of sea water. In its natural crystal form it has a pale to deep blue coloring, often with a slight greenish tint. Lighter colored stones typically are heated to remove the green component of their color. Recently, the desirability of natural greenish-blue colored stones has increased. Aquamarine is found in large crystals and is one of the few gems that does not seem to increase in per carat price as size goes up. Smaller, three-to-five carat stones of fine color can bring premium prices. Aqua, as it is often called, is a talisman for sailors, and was carried aboard most early sailing vessels voyaging into uncharted waters. A member of the beryl group of stones, aqua can easily be confused with blue topaz, a less expensive stone.
Aqua is found worldwide, with North American deposits in Colorado and California, as well as several other states.
D I A M O N D |::| Mohs' Hardness -- 10
The name diamond comes from the ancient Greek word, Adamas, or unconquerable. It is the hardest of all gems, ranking 10 on the Mohs' Hardness Scale (a listing of comparative gemstone hardness). A diamond's brilliance, hardness and durability, along with good marketing and promotion, have made diamonds the most sought after gemstone in the world today.
There are significant diamond deposits in South Africa and Siberia, and a recent find in Australia. Diamonds have been discovered and commercially mined on a small scale in Canada, and the state of Colorado. It has been reported that a diamond miner must dig approximately one ton of rock for every half carat of diamond found. Color grading of diamonds starts with the letter 'D' as the finest grade of white, and progresses through the alphabet as tint levels increase. Clarity, signifying the level of inclusions in the gem, begins as Flawless, and moves through VVS, to VS, to SI to I or included grades.
E M E R A L D |::| Mohs' Hardness 7.5 - 8
Desired even in Biblical times, the emerald is one of the oldest known gemstones. This green member of the beryl gem family has been found in ancient tombs, royal treasuries, and even in sunken sailing ships. The most prized stones are usually associated with the Muzo mine in Columbia, but extremely fine gems also come from Zambia in Africa, and from a few specific mines in Brazil.
The finest Colombian stones typically have a slight bluish cast to their color, while the Zambian stones are noted for their clarity, or minimal amount of inclusions. Virtually all emeralds have some inclusions, and gemologists agree that if the emerald under observation is inclusion free, it's likelihood of being genuine is highly suspect.
While emeralds are relatively hard and durable, they are somewhat brittle and can be damaged with hard impact.
P E A R L or PINK TOURMALINE |::| Mohs' Hardness Pearl 3 - 4 * Tourmaline 7 - 7.5
In today's retail market two stones are normally offered as the birthstone for June. Pearls have long been the gem identified with this month, but since the 1960's pink Tourmaline has gained acceptance as an additional birthstone for June. (Alexandrite is sometimes listed as June's birthstone, but its rarity and cost make alexandrite an unlikely choice for most consumers.)
Pearl necklaces have been a staple in women's jewelry for many years. Stud earrings, pins, pendants and rings are all found set with pearls. Recently the Japanese hold on cultured pearl manufacturing has been challenged by both the Americans and the Chinese.
The second June gem, Pink Tourmaline, is mined in gem grades in California and Maine, as well as Brazil, Africa, and other countries. Hot pink and pastel pink colors of tourmaline are often used in designer jewelry pieces, as their cost and durability make them an excellent choice.
R U B Y |::| Mohs' Hardness 9
The term 'Burma Ruby' has been used for years to describe the finest grades of ruby, the common name for red corundum. The Burma term came into use when most all of the world's finest rubies were mined in Burma (now Myanmar). Fine rubies are also mined in Thailand and East Africa. Thai stones typically are somewhat more purple in color, and the African gems are somewhat more brownish than Burma rubies. It should be noted, however, a top gem grade stone can come from any geographic location.
Rubies are second in hardness to diamonds, and as such they are extremely durable in everyday wear. Large, fine stones are rare, and synthetic varieties have been manufactured since the late 1800's. This red gem is one of the most expensive colored stones, and price escalates quickly with size. Rubies are often mounted with diamonds to enhance their red color, but a fine ruby has enough of a visual impact to make it an excellent stand alone stone.
P E R I D O T |::| Mohs' Hardness 6.5 - 7
A likely reason peridot has never achieved wide popularity may be due to the fact that most consumers have never seen a fine peridot. The typical peridot jewelry piece normally is constructed with a pale, somewhat washed out, inexpensive example of this green stone.
Fine peridot is a vivid, dark apple green color, and when cut to proper proportions is full of life and brilliance. Peridot is somewhat soft, and care should be taken in its everyday wearing. Large stones are rare, and price goes up quickly for nicer stones over five or six carats in weight.
Peridot is mined in several locations, and it is typically found in areas of prior volcanic activity. The most recent large find is in China, and quantities of gem grade material are found in Arizona.
It is correct to pronounce peridot as peri-dough, as well as perri-dot, and it may also be correctly referred to as olivine.
S A P P H I R E |::| Mohs' Hardness 9
Blue is the color most consumers associate with the sapphire branch of the corundum gem family. However, sapphires can be found in all colors of the spectrum, with the exception of red (red corundum is called ruby).
This hard, durable gem has been used by artisans in jewelry construction since the earliest days of gemstone adornment. In its blue form, sapphires' hue can range from an ice colored, pale blue-gray, to an extremely dark blue-black. The shade of blue most valued is called 'corn-flower blue', a soft yet intense, pure blue. Other desired colors are yellow, purple, and pink. Vivid colors are more desired than pastel shades. A rare color of orange-pink mix, is called Padparadschah.
Deposits are throughout Asia and Africa, with a find of high quality gems in Montana. Natural six-rayed star stones, cut in cabochon, are often used in mens' jewelry. Synthetic sapphires have been produced since the late 1800's.
O P A L |::| Mohs' Hardness 5.5 - 6.5
Possibly no stone used in jewelry manufacturing today spans such a wide range of prices as opal. At the low end of the pricing structure is milky opal with a few small flecks of color. These inexpensive stones are widely used in silver and light weight gold, or even gold plated jewelry. At the other extreme and commanding top dollar are Lighting Ridge, Australian stones. Fine examples of these gems have a dark to black crystal base, and a full range of colors displayed in random patches that seem to be suspended within the stone. Fine Lightning Ridge stone can sell for as much as diamonds.
Thin sheets of opal are sometimes glued to a base material and called 'doublets'. If a clear cap is added to this doublet, a 'triplet' is created. Boulder opal are when a portion of the natural ironstone base rock is left attached to the opal as it was taken from the ground.
Opal is a somewhat soft stone, and care should be taken in wearing opals. However, many antique opal jewelry pieces have survived the test of time.
Primary opal sources are Australia, Mexico, and Idaho. Also accepted as an opal birthstone substitute is Tourmaline (see June, pearl-tourmaline).
T O P A Z |::| Mohs' Hardness 8
The November birthstone is found naturally in many colors: yellows, pinks, oranges, browns and even colorless. Reportedly, natural blue gems have also been mined in Russia, but the typical blue topaz found in the marketplace has been irradiated in a lab to obtain its blue coloring.
Topaz is a relatively hard stone, but it has a cleavage plane which can sheer if the gem is hit hard. Properly cut stones position this cleavage plane on an angle to minimize this possibility. Topaz crystals are found in large sizes, and per carat price does not carry a significant premium as gem size increases.
Natural crystals tend to be somewhat long in relationship to width, and polished gems are often cut in this same long-narrow fashion; well proportioned gems carry a premium price. Citrine, a yellow quartz, is sometimes incorrectly called 'golden Topaz', but this name is misleading and should be avoided. Major topaz mines are in Brazil, Mexico and Sri Lanka.
Z I R C O N |::| Mohs' Hardness 6.5 to 7.5
Zircon is one of the most brilliant of all colored gems. Colorless zircon was commonly used as an early diamond substitute, and zircon in all of its assorted natural colors has been used in jewelry since early times.
The natural colors of the stone are honey yellow, orange, red, and various shades of green and blue. Less desired brownish colors are often heated to turn them colorless or blue, with some of these shades possibly reverting back to their natural color if exposed to strong UV light.
The stone is somewhat brittle, and the girdle edges of the stone are easily damaged. Despite these drawbacks, zircon is a beautiful, brilliant gem, and makes wonderful jewelry. Deposits of the stone are primarily in southern Asia