|
Guide
|
Gemstone GlossaryAlexandrite
A relatively young modern gem, alexandrite was first founded in Russia in 1830 Alexandrite was discovered on the birthday of the Russian Czar Alexander II, and it was named in his honor. , the red and green colors of the alexandrite mirrored the Imperial Russian flag and the gem was named after him. Alexandrite is mined in Russia, Brazil, Burma, Ceylon, and Rhodesia. Laboratory-produced Alexandrite is common, and it is often sold as natural alexandrite. Alexandrite has a hardness of 8.5 and a specific gravity of 3.64-3.74. Amber
Amethyst
Clergymen wore amethyst with the belief that it brought emotional balance, while British regalia were decorated with amethyst during the Middle Ages as a symbol of royalty. It has been associated with many myths, legends, religion and numerous cultures. Amethyst is a purple quartz, a relatively common gemstone, is a relatively common gemstone. Amethyst is usually purple, but can range in color from pale lavender to a very deep, reddish purple to a milky color to green. Deeper-colored amethysts are more highly valued. Ametrine
Ametrine is a variety of quartz, a mixture of amethyst and citrine. Ametrine is partially purple and partially orange-yellow. Aquamarine
The serene color of aquamarine is known to cool the temper, allowing the wearer to remain calm and levelheaded. Its color suggests coolness and often is worn in spring and summer. Colors range from greenish blue to blue-green in light tones. The color is usually more intense in larger stones. Today, blue aquamarines are more highly valued, but this was not true in the past, when sea-green stones were prized. Heat-treatment turns greenish stones bluer. Some aquamarine fanciers prefer the greenish hues, saying the greener tones remind them more of the sea. The best aquamarines come from Brazil. Large aquamarines are relatively common. Aquamarines are usually faceted but when they are cabochon cut, a cat's eye effect or asterism may appear. Aquamarines belong to the beryl family of stones. Aquamarine has a hardness of 7.5-8 and a specific gravity of 2.65-2.85. Black Opal
CabochonA cabochon is a stone that has a rounded, domed surface with no facets. A cabochon garnet is also called a carbuncle. Chalcedony
Citrine
The name citrine is derived from the French word "citron," meaning lemon. Most citrine available was at one time amethyst. In forming citrine, the gemstone is heated, changing its color to a brilliant gold. Citrine should be kept out of strong light or heat to preserve its color to last many generations. Citrine can be found in a variety of shades ranging from pastel yellow to orange. It is one of the most affordable of gemstones and plentiful in nature. Citrine is found most frequently in Brazil, Bolivia and Spain. In ancient times, citrine was carried as protection against snakes and evil spirits and thoughts. Cubic Zirconium
Cubic zirconium (also known as cubic zirconia) is an inexpensive, lab-produced gemstone that resembles a diamond. Cubic zirconia was developed in 1977. Cultured Pearls
Because natural pearls are so rare and difficult to recover from the ocean's depths, man invented the technique of culturing salt and freshwater pearls from oysters and other mollusks carefully seeded with irritants similar to those produced by nature. The painstaking effort of culturing is one of the most dramatic examples of man's quest to coax beauty from nature. Due to demand for perfectly matched white pearl strands, cultured, fresh and saltwater pearls are often bleached to achieve a uniform color. They may also be polished in tumblers to clean and improve their luster. Pearls are most commonly thought of as white, but they are actually produced in many colors, including gold, yellow, champagne, pink, peach, lavender, gray, and black. Produced by a living organism, pearls require special care because they contain calcareous crystals that are sensitive to chemicals and acids. To care for your cultured pearls, avoid using perfume, hairspray, abrasives, solvents, and nail polish removers while wearing them. Like your skin, cultured pearls contain water and may dehydrate and crack if exposed continuously to arid conditions. Diamond
Observe a woman's eyes as they sparkle and dance at the sight of a diamond. As the April birthstone, diamonds are the ideal gift for a loved one, but now you can make a shift from the traditional diamond. Get creative and give the ultimate gift of beauty: a fancy-colored diamond. Fancy-colored diamonds are a natural, rare and truly exotic gem of the Earth. Colors range in intensity from faint to vivid in yellow, red, pink, blue and green. The more saturated the color, the higher the value. In fact, a diamond sparkling with intense color is so rare that it can be valued higher than a colorless diamond. It is estimated that only one out of every 10,000 natural diamonds is fancy-colored. Emerald
Emeralds were long thought to have healing powers, especially for eyesight. During the renaissance, emeralds were used as a test for friendship among the aristocracy; an emerald given to a friend would remain perfect as long as the friendship endured. Emerald, derived from the word "smaragdus," meaning green in Greek, was mined in Egypt as early as 330 BC. Today, most of the world's emeralds are mined in Colombia, Brazil and Zambia. Perfection in emerald, as in all things, is among the most rare of nature's treasures. When they are mined from the earth, almost all emeralds have unique birthmarks that distinguish them as truly natural gemstones. These flaws and cloudiness, called jardin, are very common in emeralds. To understand the journey your emerald has traveled from the earth to you is to gain special insight into its magic. The availability of high-quality emerald is limited. Consequently, treatments to improve clarity are regularly performed. Early gem merchants sought to purify the transparency of their emeralds by immersing them in clear oils or paraffin. They found that clear oils and waxes rendered surface fissures less visible to the eye. Today, we have many sophisticated technologies with which to enhance the clarity of emeralds. In addition to the oils and waxes of ancient methods, we now use clear resins to penetrate the open fissures surfacing in the stones. Hardeners are often added to solidify these liquids. This step prevents the resin from evaporating, thus making the clarity enhancement more stable than oiling or waxing the gem. However, these measures are not permanent, so emeralds must be cleaned with care. Synthetic emeralds (developed by Carroll Chatham in the 1930's) have fewer imperfections and are very hard to distinguish from natural emeralds. Emeralds belong the beryl group of stones which also includes aquamarines, morganite, and chrysoberyl). Emeralds have a hardness of 7-8 and a specific gravity of 2.6 - 2.8, although emerald itself is quite durable, the garden of inclusions may make individual gems vulnerable to damage if handled roughly. FireA stone's fire is the streaks of brilliant color within it. Good quality opals have a lot of fire. Fire OpalFire opals are a type of opal that is firey orange to red in color (but have no opalescence). These opals are rarely transparent - they are usually milky. Opal is a mineral composed of silica (and some water) and is a species of quartz. Many opals have a high water content - they can dry out and crack if they are not cared for well (opals should be stored in damp cotton wool). Opals have a hardness of 5.5 to 6.5 and a specific gravity of 1.98-2.50. Fire opals are found in Western Australia, Mexico, Brazil, Guatemals, and Honduras. FlawA flaw is a an imperfection in a gemstone. Flaws include: cracks, inclusions of other minerals or liquid-filled cavities. A flawless stone is called "clean." Flaws can greatly reduce the value of a stone, but in some cases, like moss agate or rutilated quartz, the "flaws" increase the value of the stone. GarnetGarnet is the January birthstone. Garnet is said to give the wearer victory, chastity, truth and fidelity. Garnet comes in virtually a rainbow of colors, from deep red to rich orange and golden hues, striking greens, and petal-soft colors of violet and lavender. The stone derives its name from the Latin granatus, meaning grain. Garnet grains were compared to the seeds of a pomegranate. This gem was thought to give its wearer guidance and illumination in the night. Legend has it that Noah used a garnet lantern to navigate the Ark through 40 days and nights of torrential rain. As a general rule, garnets are not enhanced. Garnets are any of a group of semi-precious silicate stones that range in color from red to green (garnets occur in all colors but blue). Some garnets used as gemstones include pyrope (the deep red garnet), almandine, spessartine, grossular, the iron-aluminum dark red garnet (also known as the carbuncle stone), Uvarovite (rare), and the lustrous Andradite (which includes the valuable green demantoid garnet, Topazolite , and Melanite). Red garnet is the birthstone for January. Garnet has a hardness of 6-8 and a specific gravity of 3.5 - 4.3.
GemstoneA gemstone (also called a precious stone) is a mineral that is valuable, rare and often beautiful. A few organic materials, like amber, coral and pearls are also considered gemstones. HardnessA substance's hardness is how resistant it is to being scratched. Hardness is measured using the Mohs Scale of Hardness. In the Mohs scale, one substance is harder than another if it can scratch it. For example, a diamond will scratch garnet, but not the other way around, so a diamond in harder than garnet. Heat TreatmentHeat treatment is the heating of stones to a high temperature in order to enhance the color or clarity. For example, blue-green aquamarine becomes blue with heat treatment and brown zircon becomes blue or clear. chromium .02%, and zinc .02%; the remaining 0.16 percent is sulfur, chlorine, and water. InclusionAn inclusion is a particle of foreign matter contained within a mineral. Inclusions can be solid, liquid, or gaseous. Many inclusions decrease the value of a stone, but some, like rutile forming asterisms in star sapphires and needles in rutilated quartz and tourmalinated quartz, are prized. InlayAn inlay is a piece of material (often stone or glass) that is partially embedded in another material (usually metal) such that the two materials make a level surface. Iolite
IrradiationIrradiation is the act of being exposed to radiation. Many stones (like ite) are irradiated in order to enhance their color. Being irradiated changes the crystal structure of the mineral by moving electrons. Irradiation techniques bombard the crystal with high-energy radiation (like gamma rays), producing a stone with very little radioactivity and a change of color.
KnotA knot is a flaw (a mineral inclusion) in a gemstone (usually a diamond) that is at the surface of a gem after polishing. The knot is a small raised bump on the finished gemstone. Kunzite
LapidaryA lapidary is someone who cuts and polishes gemstones. Lapis Lazuli
LusterA stone's luster is its sparkle or sheen - the way it reflects light. The luster depends on the nature of the stone's surface reflectivity. Some types of luster include: adamantine (also called brilliant or diamond like, like a faceted diamond), earthy (with little reflectivity- also called dull, like shale or clay), greasy (like nepheline or apatite), metallic (also known as splendent, like pyrite or marcasite), resinous (like amber), pearly (with an iridescent reflectivity, like pearls or mica), pitchy (tarry minerals that are radioactive, like uraninite), silky (with a fibrous structure, like some tiger's eye or satin spar), vitreous (also known as glassy, like olivine, transparent quartz, or obsidian), and waxy (like halite or turquoise). A pearl's luster is derived from its nacre. Mohs ScaleThe Mohs Scale of Hardness measures a substance's hardness, that is, how resistant it is to being scratched. In the Mohs scale, which ranges from 1 to 10, one substance is harder than another if it can scratch it. For example, a diamond (hardness = 10) will scratch garnet (hardness = 6.5-7.5), but not the other way around, so a diamond is harder than garnet. This scale was invented by Austrian mineralogist Friedrich Mohs (1773-1839). Moonstone
Onyx
Opal
Opals range in color from milky white to black with flashes of yellow, orange, green, red and blue. An opal's beauty is the product of contrast between its color play and its background. White opal can best be described as a translucent to semi translucent gemstone that displays an array of colors against a white or light gray body color. The main source of white opal is found in Australia and Brazil. Black opal can be described as a translucent to opaque gemstone that displays a variety of colors against a black or other dark color. The main source of black opal is found in Australia. Fire opal is transparent to translucent gemstone that displays brown, yellow, orange or red color. This gemstone does not show an array of colors within it. It is often referred to as Mexican opal, gold opal or sun opal. The main source of fire opal is found in Mexico. Many opals have a high water content - they can dry out and crack if they are not cared for well (opals should be stored in damp cotton wool). Opals have a hardness of 5.5 to 6.5 and a specific gravity of 1.98-2.50. Opals are found in many places worldwide, but Australia has a tremendous variety of beautiful opals. Opal should not be exposed to heat or acid and should be cleaned only with a soft cloth, never with any kind of cleaning solution. Padparadscha Sapphire
Pearl
Peridot
Peridot is relatively soft and should be spared rugged, regular wear if worn in a ring. Peridot is a gemstone that forms deep inside the Earth and is brought to the surface by volcanoes. In Hawaii, peridot symbolizes the tears of Pele, the goddess of the volcano. Peridot is often used in healing ceremonies by Hawaiian Kahunas. Today, the majority of the peridot supply comes from Arizona, yet it is also mined in China, Myanmar and Pakistan. Most peridots are from a volcanic island in the Red Sea, Zebergit/St. John, the "Serpent Isle." Peridots have been found in meteorites. Peridot has a hardness of 6.5. Peridot cat's eye also exists. Precious StoneA precious stone (also called a gemstone) is one that is valuable and rare. Rhodolite
RoughRough stones or crystals are in their natural state, they are neither cut nor polished. Rubellite
Ruby
Throughout most of recorded history, ruby has been the most valuable of gems. It was believed wearing a fine red ruby bestowed good fortune on its owner - although the owner must have already had good fortune enough to possess such a rare and beautiful gem! Despite all the best efforts of gem merchants to use technology to enrich color, fine ruby is still exceptionally rare. After being extracted from the earth, rubies today are commonly heated to high temperatures to maximize the purity and intensity of their red hue. Impurities may also dissolve or become less noticeable after heating. However, heating will only improve the color if the gem already contains the chemistry required. Occasionally rubies with small imperfections are permeated with a silicate byproduct of the heating process, which helps to make small fissures less visible. This enhancement, like heating, is permanent. Another enhancement in rubies is diffusion with beryllium, or a similar element, which artificially adds color to the stone. Whether enhanced or not, rubies remain among the most durable of gems. Ruby is a variety of the gem species, corundum. It is harder than any natural gem except diamond, which means a ruby is durable enough for everyday wear. Fine-quality ruby is extremely rare and the color of the gem is most important to its value. Rubies range in color from the classic deep red to pink to purple to brown. The finest color is a medium or medium dark, vivid, red or slightly purplish red.
Rubies have commanded the highest prices for a colored gem, but if red is your color and you are budget-minded, you have numerous alternatives. Spinel, tourmaline, almandite, pyrope or rhodolite garnets, all have fascinating hues to illuminate fire and passion. Sapphire
Sapphire is derived from sappheiros the Greek word for blue. Sapphire is a variety of corundum. Ruby is the red variety of the mineral corundum. Sapphire is the name for all other colors of corundum other than red. The gemstone sapphire is allochromatic which means it can be in every color. A gem quality sapphire is rarer than diamonds. The royal blue sapphire is found in Kancha Thailand and the cornflower blue sapphire is found in Montana. White sapphires have been used as diamond substitutes. One of the most popular sapphire colors lately are the pink sapphires. Jewelry made with every color of sapphire is called rainbow sapphire. Yet the perfect sapphire is as rare as the finest work of art. Thus, over the centuries, we have developed methods to enhance the purest hues of sapphire. This is now commonly achieved by controlled heating of these gems, a technique that not only improves color but also improves clarity. Heating sapphires is a permanent enhancement, as lasting as the gemstones themselves. Another enhancement in sapphire is diffusion with beryllium, or a similar element, which artificially adds color to the stone. Sapphire has a hardness of 9 and a specific gravity of 3.9 - 4.1. Star Ruby
Star Sapphire
Step CutThis faceting style is composed of rows of facets that resemble the steps of a staircase, examples of this are emerald cut and baguettes. StriationsStriations are grooves, lines and scratches found naturally in some minerals. Tanzanite
Legend has it that the effect of heat was first discovered when some brown gem crystals lying on the dry earth were caught in a fire set by lightning that swept through the grass-covered hills. The Masai herders driving cattle in the area noticed the beautiful blue color and picked the crystals up, becoming the first tanzanite collectors. From the awe-inspiring grandeur of Mt. Kilimanjaro, in Tanzania, Africa comes the discovery of a century, a gem so precious, so rare that it is found exclusively in a tiny area - tanzanite. Discovered in the late 1960s, tanzanite is the official December birthstone of the AGS. Tanzanite, exhibits a rich, violet-blue color, which the stone is treasured. Tanzanite can be less expensive than sapphire and is often purchased as an alternative. Today, tanzanite's increase in popularity has createdits own market and is appreciated for its beauty and brilliance. Although, there have been wide fluctuations in the gem's supply and price level, due mostly to Tanzania's volatile political, economic and social conditions. Tanzanite is heat-treated to achieve its color. It is carefully mined to avoid damage to the precious limited supply available. Colors range from blue to purple. One of the most highly valuable tanzanite is medium dark in tone, vivid in saturation and slightly violet-blue. Tanzanite (strontium-rich Calcium-aluminum silicate) is a valuable, transparent, blue-violet type of zoisite resembling sapphire. Tanzanite has a hardness of 6 and a specific gravity of 3.35. It is often heat-treated in order to produce a deeper blue-violet color Topaz
The most valuable Topaz is called "Imperial", after the Russian Czars of the 1800's, and features a magnificent Orange body color, with pinkish Red undertones. Topaz also comes in Yellow, Pink, Purple, Orange, and the popular Blue hues. Topaz has a hardness of 8 and a specific gravity of 3.5-3.6. Tourmaline
Tsavorite
Turquoise
The name turquoise comes from the French expression "Turkish stone," that originated in the thirteenth century when the gem most likely first arrived in Europe from Turkish sources. The finest color is an intense blue. Turquoise may contain narrow veins of other materials either isolated or as a network. They are usually black, brown, or yellowish-brown in color. Known as the matrix, these veins of color are sometimes in the form of an intricate pattern, called a spider web. Persian turquoise is robin's egg blue and has no matrix. North American turquoise is greener and has a matrix streaks. It can also be translucent to opaque. Turquoise is plentiful and available in a wide range of sizes. It's most often used for beads, cabochons, carvings and inlays. Although its popularity fluctuates in fashion, the biggest market for turquoise in the American Southwest Turquoise is a non-translucent, porous semi-precious stone that is usually cut as a cabochon. Turquoise was first found in Turkey, hence its name. Turquoise is found in desert regions worldwide. Persian turquoise is robin's egg blue and has no matrix (streaks of the mother stone from which they were found). North American turquoise is greener and has a matrix streaks. Over the years, oil from your skin is absorbed by the stone and it will change color slightly. Turquoise has a hardness of 6 and a specific gravity of 2.60-2.85. Watermelon Tourmaline
Zircon
|
As days pass into years, change is the only constant facet. Change can be anticipated, sometimes hopeful, and sometimes feared. In regards to alexandrite, one of the birthstones of June, change is beautiful. Alexandrite is an extremely rare chrysoberyl with chameleon-like qualities whose color transforms from a deep green in daylight to a purplish red in candle light. Make change exciting, let alexandrite jewelry reflect the beauty of years to come.
Amber is translucent fossilized tree resin (from conifers), a natural hydrocarbon that comes in many colors, including yellow, reddish, whitish, black, and blue. Amber is flammable. Rubbing amber produces static electricity. The word electricity comes from the Greek word or amber, "elektron." It used to be thought that amber possessed magical powers that protected the wearer from evil. Pressed amber consists of small pieces of amber that have been fused together to form a larger piece. Fake amber is easily made from plastics, and buyers must beware of cheap imitations sold as natural amber. Amber has a hardness of 2.5 and a specific gravity of 1.05-1.10.
In celebration of a February birthday one may chose to have a few drinks with friends, ancient Greeks and Romans believed it to ward off the intoxicating powers of Bacchus, the God of Wine. Fine amethysts are featured in the British Crown Jewels and were also a favorite of Catherine the Great and Egyptian royalty. Great thinkers like Leonardo da Vinci believed that amethyst could dissipate evil thoughts and quicken the intelligence. Is also said to this gemstone is thought to impart clarity of mind, health, luck and wit to its wearers. In ancient times it was a symbol of peace. 
The birthstone of March is aquamarine. Named by the Romans about 2,000 years ago, its name is derived from the Latin word aqua, meaning "water," and marina, meaning "sea". It is a light blue like the colors of the Mediterranean sea. The aquamarine is said to give courage, victory and confidence. Aquamarine is said to be mermaid treasure and has the power to keep sailors safe. 
Black opals are a valuable type of precious opals with a dark ground color. They are luminous, iridescent, and frequently have inclusions of many colors ("fire"). Opal is a mineral composed of silica (and some water) and is a species of quartz. The rainbow-like iridescence is caused by tiny crystals of cristobalite. Many opals have a high water content - they can dry out and crack if they are not cared for well (opals should be stored in damp cotton wool). Opals have a hardness of 5.5 to 6.5 and a specific gravity of 1.98-2.50. Black opals are found in Australia.
Chalcedony is a family of minerals (microcrystalline quartz) that are often milky to gray to bluish in color. Chalcedony includes agate, carnelian (waxy red), chalcedony (blue), chrysoprase (green), onyx (black and white), bloodstone, sard (brownish-red), jasper (hornstone), seftonite, and others. Chalcedony is porous and translucent. Chalcedony has a hardness of 6.5-7 and a specific gravity of 2.6.
Citrine, the birthstone of November is recognized as the healing quartz. This golden gemstone supports vitality and health, encouraging and guiding hope, energy and warmth within the wearer. While citrine supports warmth of the soul, it can also brighten and heat up your wardrobe this fall season.
Pearl is the June birthstone. Pearls are formed when an irritant, such as a piece of sand, enters an oyster. The oyster coats the piece of sand over and over and a pearl is formed. An arabic legend states that pearls are formed when dew drops fall into the ocean. Pearls have been associated with Venus, which was named after the Roman goddess of love. According to ancient Chinese legend, the moon holds the power to create pearls, instilling them with its celestial glow and mystery. Pearls have been treasured for their lustrous, creamy texture and subtle iridescent reflections since the dawn of humankind. 
Some say that those born in April are the luckiest as the diamond is the April birthstone. Since ancient times, diamonds have been treasured for their brilliance and fire. Diamonds are also the symbol of love. Diamonds are prized for their brilliance, elegance, and purity, and have captivated our imaginations for thousands of years. The diamond actually derives its name from the Greek word adamas, meaning unconquerable and indestructible. The ancient Greeks believed that diamonds were splinters of stars that had fallen to the earth. Some said that they were tears of the gods. Kings of old wore diamonds in their armor to protect them in battle.
Emerald is the May birthstone. The emerald is a green that brings to mind the colors of spring. Emerald is said to represent hope, success and rebirth. Emerald, to many, symbolizes rebirth and the abundance of the life force. The Vibrantly colored emeralds often have the ability to lift one's spirit on sight. The rich green hue brings to mind the regeneration of life inspiring and hope of new possibilities; no wonder the emerald is believed to empower the owner with foresight into the future, good fortune, youth and rebirth. 
Grossular - Colorless, orange, yellow, pink, or brown 
Iolite, also known an water sapphire, is a transparent, violet-blue, light blue, or yellow-gray mineral. Iolite is pleochroic; a single stone showing many colors (in the case of Iolite, violet-blue, light blue, and yellow-gray). Iolite is not rare and has a hardness of 7 - 7.5 and is found in Sri Lanka, India, Madagascar and Burma.
Kunzite is a transparent pink, light pink, or light purple gemstone that resembles roze quartz. It is a variety of the mineral spodumene. Kunzite can fade after prolonged exposure to light. Kunzite is also called "evening stone," because of its propensity to fade in bright light. The original color of some kunzite stones can be restored or even intensified by irradiation. It is usually used as a large stone and is easily chipped; small stones of kunzite are difficult to cut. Kunzite is often used in pendants. Kunzite has a hardness of 6-7 and a specific gravity of 3.1 - 3.2. Kunzite was first found in 1902 in Pala, California, USA, and is named for the gemologist George F. Kunz. Kunzite's chemical composition is LiAlSi2O6 was very popular early in the 20th century and was extensively used in Art Nouveau jewelry.
Lapis lazuli is a rich blue opaque, semi-precious stone that has been used in jewelry since ancient times. Ground-up lapis lazuli was once used as a pigment for oil paintings. Lapis lazuli is often dyed to deepen and improve its color. Lapis has a hardness of 5.5; it chips and scratches easily. It has a specific gravity of 2.4 to 2.9. Water can dull its sheen. Lapis lazuli contains the minerals calcite (which decreases its value), pyrite (which can increase its value), and sodalite. Swiss lapis is not Lapis lazuli at all; it is dyed jasper. Denim lapis is relatively pale, low-grade, inexpensive lapis from Chile; it is the color of denim cloth because of calcite inclusions which whiten the color and lower the value).
Moonstone (orthoclase) is a semi-translucent stone that is made of albite and orthoclase feldspar. It is usually whitish-blue, but can be colorless, yellow, orange, gray, or even reddish. Moonstone is usually set as a cabochon. Moonstone has a hardness of 6 and a specific gravity of 2.57. It is monoclinic; it has one two-fold axis of symmetry. Adularia is a common type of moonstone. Oligoclase is another type of moonstone; Labradorite and albite are rare forms.
Onyx is a semi-precious stone that is black and white, generally arranged in layers. It is a form of agate with parallel banding. This structure lends itself to cameo making. Onyx is a species of chalcedony (microcrystalline quartz). It also come is green-brown which is used in place of marble in homes.
Opal is the October birthstone. The name opal was derived from the Greek, "Opallos," meaning to see a change (of color). The opal captures images within the depths of its sparkling brilliance. Ancient kings treasured opal for its mystical prism of colors and firey colors and many believe that the mysteries of love can be exchanged through this enchanting gem. Opal is said to be a symbol of hope and beauty.
Padparadscha sapphires (also spelled padparadschah) are a rare pink-orange variety of corundum or the synthetic equivalent. These gems are mined in Sri Lanka and are usually heat treated to improve and intensify the color. The name padparadscha comes from the Sinhalese word for lotus flower. Hardness = 9, Specific Gravity = 4.
Pearl was among the favorite gem materials of the Roman Empire. In Tudor England, the 1500s were known as "the pearl age". On his 3rd voyage to the Americas, Columbus kept his discovery of Pearls in the New World a secret, and he fell out of favor with the King of Spain. In the Orient pearl powders are sold as an aphrodisiac. For medicinal use Pearls are composed of calcium carbonate, an essential supplement for promoting strong bones and teeth, as well as the prime ingredient in stomach antacids. Pearls are unique in that they are the only gem of the sea from living creatures requiring no faceting or polishing to reveal their natural beauty. In the early 1900s the first successful commercial culturing of round pearls began. Since the 1920s cultured pearls have almost completely replaced natural pearls in the market.
Peridot is the August birthstone. This green gemstone is believed to help with nightmares, bring prosperity, fertility and healing. Peridot was once called the "gem of the sun" in ancient times. Peridot has been adored since ancient times; its history traces back more than 3,500 years when it was prized by the ancient Egyptians. Found in various shades of green, peridot is most desired in lime hues. Peridot has been credited with a host of magical powers and healing properties, such as protection against nightmares and possessing the power to ward off evil. This is a gift that shines with enthusiasm and is said to bring the wearer power, influence and a wonderful year.
Rhodolite (meaning rose stone in Greek) is a purple-red to pink-red variety of garnet and is a combination of almandine and pyrope (it is sometimes called pyrope-almandine garnet). This silicate stone has a hardness of 7-7.5 and a specific gravity of 3.5 - 4.3. The formula for garnet is: A3B2(SiO4)3. Rhodolite is found in the US, Zimbabwe, Kenya, and Sri Lanka (Ceylon). Rhodolite is not enhanced.
Rubellite (sometimes spelled rubelite) is a red variety of tourmaline. Rubellite is red in both incandescent and daylight, and is more valuable than other varieties of red tourmaline. Rubellite has a hardness of 7-7.5 and a specific gravity of 3.02-3.25. Rubellite is sometimes treated with fillers to increase the clarity of the stone.
Ruby is the July birthstone. The ruby is a lovely red gemstone and has been a favorite since ancient times. The ruby is said to be a gem of passion and promotes balance in love and all spiritual undertakings. Rubies scintillate the senses, stir the imagination and are said to guarantee health, wisdom, wealth and success in love. Gem of passion, of smoldering desire, ruby has been treasured for thousands of years. Because the ancients thought its glowing red color was due to an inextinguishable inner fire, ruby was also associated with courage and power. Rubies scintillate the senses, stir the imagination and are said to guarantee health, wisdom, wealth and success in love. 
Laboratory-produced rubies were created in the 1890's; they are difficult to distinguish from natural rubies. The biggest ruby in the word is the Raviratna, which weighs 3,600 carats. Rubies have a hardness of 9 and a specific gravity of 3.9 - 4.1. Rubies are found in Afghanistan, Australia, Brazil, Cambodia, India, Myanmar (Burma), Malagasy Republic, Malawi, Pakistan, Sri Lanka (Ceylon), Tanzania, Thailand, United States (Montana and North Carolina), and Zimbabwe (Rhodesia)
Sapphire is the September birthstone. Velvety blue. Liquid blue. Evening-sky blue. Cornflower blue. Because sapphire embodies an infinite palette of blue hues, ancients believed that the earth rested on a giant sapphire and its reflection colored the sky. But like the endless colors that appear in the sky, sapphire is also found in many other shades besides blue, from the gold of a sunrise, to the fiery reddish-orange of sunset, to the delicate violet of twilight. Sapphire may even resemble the pale white gloaming of an overcast day. In ancient times, a gift of a sapphire was a pledge of trust and loyalty. It is from this tradition that sapphire has long been a popular choice for engagement rings.
A "star ruby" is a ruby that exhibits an asterism, a six-pointed star of light (when cut as a cabochon). The world's biggest star ruby is the Rajaratna, which weighs 2,475 carats. The world's biggest double-star ruby (with a 12-pointed star) is the Neelanjali, weighing 1,370 carats.
A star sapphire is a sapphire that exhibits an asterism in the form of a colorless, six-rayed star that reflects light. Star sapphires are cabochon cut. Laboratory-produced star sapphires ("Linde stars") were developed in 1947 by the Linde company; most star sapphires today are synthetic.
Tanzanite, the ultimate prize of a gem safari, has a mesmerizing blend of rich purples and blues with a velvety deepness of color unlike any other gem. Mined only in Tanzania at the foot of the majestic Mount Kilimanjaro, virtually every tanzanite is heated to permanently change its color from orange-brown to the spectacular violet-blue color for which this precious gemstone variety is known. 
Topaz is a gemstone available in a rich rainbow of colors. Prized for several thousand years, all yellow gems in antiquity were called Topaz. This material has been associated with religious teachings representing one of the gems in the breastplate of the high-priest of Israel, and one of the foundation stones of Jerusalem. This lead much later to the present birthstone list we know today. The name may have come from the ancient isle of "Topazios" in the Red Sea, or from the Sanskrit word meaning "Fire". Often confused with the Quartz Varieties: Citrine (Yellow) and Smoky (Brown). Quartz and Topaz are not related species.
Pink tourmaline is the alternate birthstone for October. Tourmaline is a dichroic gemstone that comes in many, many different colors; it also appears to have different colors depending on the angle at which it is seen. Tourmaline has the greatest color range of any gemstone - thel ighter colors are more valuable than the darker colors. It ranges in color from pink to green to red (rubellite) to purple to blue-green (indicolite) to colorless (achroite) to black. Watermelon tourmaline is both pink and green. Tourmaline occurs as an elongate three-sided prism and is mined in Brazil, The Ural mountains in Russia, Namibia, Sri Lanka, and California. Tourmaline was only discovered in the 1700's. Tourmaline has a hardness of 7-7.5 and a specific gravity of 3.02-3.25. It is doubly-refractive.
Tsavorite is a rare, deep green variety of grossular garnet, a type of garnet, calcium-aluminum silicate. The emerald green color comes from vanadium and chromium. Tsavorite is similar to emerald, but is rarer and more durable; it also has a higher refractive index, 1.74. Tsavorite stones over two carats are considered large and are very rare. Tsavorite has a hardness of 7.5 and a specific gravity of 3.6. Tsavorite is found in east Africa; it was named by Harry B. Platt of Tiffany & Co. for the Tsavo National Park in Kenya, where this gemstone was originally found in 1967. Tsavorite is not enhanced.
Turquoise is one of the world's oldest gemstones dating back as early as 5500 BC when Egyptian royalty adorned themselves in this regal gem. Turquoise has long been considered a stone that guarantees health, good fortune and protection from evil.
Watermelon tourmaline is a tourmaline gemstone that is multicolored, going from pink to green. It grows naturally with green on the outside and pink on the inside , like a watermelon.
Zircon (zircon silicate) is a lustrous gemstone that comes in colors ranging from golden brown to red to violet to blue. Pure zircon is colorless, but most zircon stones are brown. Zircon stones can be heat-treated to become blue or colorless; sometimes, heat-treated stones revert to their original color. Clear zircon is sometimes sold (intentionally or otherwise) as diamond. It has a hardness of 7.5 and a specific gravity of 3.90-4.71.