Guide to Gemstones
Alexandrite was first discovered in the Ural Mountains of Russia in 1830 on Czar Alexander’s birthday. This rare stone has the incredible quality of naturally changing colors from a bright red in artificial light to a lucid green in natural light. Alexandrite has a specific gravity of 3.68-3.75 and a hardness of 8.5.
Amber has been treasured for thousands of years, with amber jewelry dating back to ancient civilizations such as the Egyptians and Romans. Amber is essentially fossilized tree sap. The most valuable amber comes from the Baltic region. Amber comes in hundreds of different colors, the scarcest being blue and green, and can be either transparent or clouded. Amber is believed to increase creativity and bring luck and love to its wearer. The specific gravity of amber is 1.1 and its hardness is 2-2.5.
The amethyst is a beautiful transparent violet gemstone. A member of the quartz family, the amethyst has long been valued for its beauty, ranging from a pinkish purple to a deep rich purple. Ancient civilizations attributed various mystical powers to the stone, for example the ancient Greeks who believed the amethyst prevented intoxication and would drink from amethyst goblets. Amethysts are mined in Brazil, Russia and India, among other locations. The amethyst has a hardness of 7 and specific gravity of 2.65.
The aptly named aquamarine is a member of the beryl family, a translucent gemstone ranging from pale blue to turquoise in color. Aquamarines are mainly found in Brazil, but the aquamarines from Africa are considered more beautiful and are more expensive as they are also more rare. Aquamarines were once thought to bring good luck to sailors who took them on voyages. Aquamarines have a specific gravity of 2.67-2.84 and a hardness of 7.5-8.
The word “citrine” comes from the old French word “citrin,” which translates to “lemon.” Citrines are a type of quartz, long ignored due to their abundance but gaining popularity in the latter half of the 20th century due to their reasonable cost and beautiful range of neutral tones. They range in color from pale honey yellow to deep reddish brown. Citrines are thought to bring their wearers happiness and protection and have a specific gravity of 2.65 and a hardness of 7.
Precious coral comes from the skeleton of live coral. Most of the coral found in jewelry comes from the Mediterranean or the Pacific near Japan. The skeleton forms in a rough, branchlike structure which can be polished to a glossy finish. Coral ranges in color from white to pale pink (often referred to as angelskin coral) to deep vibrant red to black, and due to its opacity and softness is often formed into beads and cabochons. Coral is believed to have protective and healing powers and has a hardness of 3.5 and a specific gravity of 2.6.
Diamonds are the hardest natural occurring mineral on earth whose unique light refracting quality has made them highly coveted for use in fine jewelry. Long admired for their strength and beauty, diamonds were believed to ward off evil and protect the wearer. Ancient Roman warriors would wear diamonds for protection during battle. The most commonly used diamonds are white, but diamonds are found in a range of colors including black, pink, yellow and red and are mined mainly in Africa, Russia and Australia. Diamonds have a specific gravity 3.52 and a hardness of 10.
Emeralds are a variety of beryl, famous for their luminous rich green color. Beryl that is a lighter green in color is not considered to be an emerald. Emeralds have been treasured since antiquity, known to be favored by Queen Cleopatra herself and considered sacred by the Incans. The stone was believed to symbolize love and increase fertility. The most magnificent emeralds are found in the mines in South America. Because the emerald stone tends to include many inclusions, fine emerald is relatively rare making it highly valuable. The emerald has a specific gravity of 2.67-2.78 and a hardness of 7.5-8.
The word “garnet” comes from the Latin word for pomegranate, referring to the resemblance of the gemstone to pomegranate seeds. Through normally associated with a rich, deep red, garnets are actually found in a number of colors, ranging from red to green the rarest of which is the blue garnet. The word “garnet” encompasses a group of ten similar gemstones, including the green tsavorite and the red rhodalite. Ancient beliefs attributed the garnet with the protective powers as well as the ability to stave off nightmares. The garnet has a specific gravity of 3.6 and a hardness of 7 to 7.5.
The term “jade” actually refers to two distinct gemstones, nephrite and jadeite. The word comes from the Spanish term for “stone of the loins,” as jade was believed to cure kidney ailments. Jadeite is the scarcer and more valuable of the two. Jade comes in a variety of colors including brown, lavender and white. The most valuable jade is what is often referred to as “Imperial Jade,” a luminous vivid green jadeite resembling the quality of jade prized by the ancient emperors. Jade is generally carved in beautiful intricate designs or shaped in the form of cabochons and the specific gravity of jade is 3.3-3.5 with a hardness of 6.5-7.
Kunzite is a relatively young gemstone, not discovered until 1902. As a marketing ploy, the miners named the gemstone after the pre-eminent gemologist George Kunz, the gem buyer for Tiffany & Co at the time. Kunzite is admired for its translucence and beautiful light violet pink shade that glows beautifully when faceted, especially in high carat stones. Kunzite is mined mainly in the United States, Madagascar, Brazil and Afghanistan. It has a specific gravity 3.17-3.23 of and a hardness of 7.
Lapis is a stunning opaque gemstone of deep blue coloring with tiny flecks of gold pyrite, but it also can be found in lighter shades of blue as well. It is one of the most ancient gemstones and believed to have magical powers. In fact, lapis was used by the great painters of the Renaissance, ground up to create a lovely blue pigment. The most beautiful Lapis is found in Afghanistan, but Lapis is also mined in Russia and Italy, among other places. Its value is based on the intensity of its color as well as the distribution of pyrite inclusions in the stone, and lapis is generally made into beads or cabochons. Lapis has a specific gravity of 2.4-2.6 and a hardness of 5.5.
The moonstone is an enchanting, luminous gemstone that shimmers in the light. It has long been regarded as having magical powers in many cultures and the ancient belief was that the gemstone was actually formed from frozen moonlight. Moonstones come in a variety of colors ranging from a beautiful translucent blue to an orange color, all displaying the same shimmering quality. Moonstones were often used in jewelry during the Art Nouveau period, when artists at the time focused on creating sensual, feminine pieces. Moonstones have a specific gravity of 2.64-2.68 and a hardness of 6-6.5.
The Ancient Greeks believed onyx to have come from the fingernails of the goddess Venus. Other cultures attribute onyx with mystic healing powers. Onyx is a form of quartz, available in a number of colors such as white and brown, but with black being the most common as well as most popular. Onyx is most often polished in the form of cabochons, but is also popular for carving cameos and beads. It is mined throughout the world, but mostly in Brazil, India and Africa. Onyx has a specific gravity of 2.65-2.66 and a hardness of 7.
Precious opals are mainly found in Australia, long treasured for the stunning variety and interplay of colors they exhibit. Centuries ago, opals were believed to bring the wearer good fortune, and ancient aborigines believed they were holy gemstones. Opals have high water content, making them relatively fragile jewels and must be handled with care. They are usually used in jewelry in the form of polished cabochons. There are many different varieties of opals, such as the fire opal found in Mexico, named for its characteristic vibrancy, but lacking the shimmering interplay of color of the Australian opal. Opals have a hardness of 5.5-6.5 and a specific gravity of 1.4 – 2.2.
Pearls are organic gemstones, formed when the soft tissue of an oyster is irritated by a small particle which is then covered with multiple layers of an iridescent organic compound called nacre. At one point pearls were extraordinarily valuable. The Cartier building on Fifth Avenue in Manhattan was purchased in the early twentieth century for a necklace of natural pearls at that time valued at one million dollars. With the advent of cultured pearls (invented by Mikimoto of Japan), the value of pearls dropped. Perfectly round pearls are most rare and thus most valuable, as are specially colored pearls such as Black Tahitian Pearls. Most fine natural pearls today are found in the South Sea. Pearls have a specific gravity of 2.68-2.85 and a hardness of 2.5-4.5.
Peridots have been used in jewelry since the time of Ancient Rome and Egypt. Peridots exhibit a beautiful translucent golden lime green color that varies in intensity depending on the iron content of the stone. The most valuable peridots are found in the Middle East, but are also mined in a number of other sites such as Africa and the United States. They are found in stones created by volcanic eruptions or at sites of meteor crashe. Peridots have a specific gravity of 3.31-3.48 and a hardness of 6.5-7.
The term “ruby” comes from the Latin term for “red.” Rubies have been valued for thousands of years as the most precious of all gemstones, even above diamonds. A relative of the sapphire, rubies are valued for their beautiful rich red color. Certain rubies also possess a silky luster with a refracted star shape showing when light hits a certain way, called star rubies. The most determinative factor of a ruby’s value is the intensity of its color. Rubies are mined in a few locations throughout the world, including Vietnam and Africa. Rubies have a specific gravity of 3.9-4.1 and a hardness of 9.
Though mainly thought of as a blue gemstone, sapphires actually come in a variety of colors such as yellow and pink, and stones of these colors are referred to as “fancy sapphires.” They have long been thought to bring their wearers wisdom and were believed to be gemstones from the heavens. Sapphires are of the same composition as the ruby, and thus there are no red sapphires as these are considered rubies. Sapphires are valued in terms of their clarity, color and vividness. They are mined throughout the world including the United States and Africa and, like rubies, have a hardness of 9 and a specific gravity of 3.9-4.1
Tanzanite is found only in the African state of Tanzania at the foot of Mount Kilimanjaro, hence its name. It is a stunning translucent blue gemstone with a trace of violet, discovered in the latter half of the twentieth century. The stones intense color made it immediately popular for use in jewelry. While the stone ranges in color from a reddish purple to lavender, the most popular shade is the blue tinged with violet. The specific gravity of tanzanite is 3.35 and the hardness is 6.5-7.
The most popular color of topaz is yellow, but it also is found in other colors such as red, blue and pink. For thousands of years, it has been regarded as having special mystical powers such as the powers of protection, healing and fertility. The ancient Egyptians believed that the topaz was colored by the rays of their sun god. It is important to distinguish topaz from topaz quartz, a stone of lesser value. Topaz is mined throughout the world in locations such as Brazil and Russia, and in centuries past was available exclusively to royalty. It has a specific gravity of 3.52-3.56 and a hardness of 8.
Tourmalines come in a huge spectrum of colors, including bicolored and multicolored tourmalines. In fact, the word “tourmaline” comes from the tendency of tourmalines to display more than one color in a single stone. They are believed to increase creativity of their wearer. Tourmalines come in more colors than any other gemstone, and different colors have been given distinct names. For example, rubellite is the name for a vivid red tourmaline. Tourmalines also come in yellow, blue, green, orange, pink, and other colors. Tourmalines are mined throughout the world including South America and Africa. The most valuable are the blue and green stones mined in Brazil. Tourmaline’s specific gravity is 3.03-3.25 and it has a hardness of 7-7.5.
Turquoise is a beautiful sky blue opaque stone, valued for thousands of years as a holy stone. Other cultures believed in its ability to protect against evil. The most beautiful turquoise is found in Iran, called “Persian Turquoise,” valued for its beautiful vibrant color. Deposits are also being mined in other countries like the United States and China. Turquoise is usually made in the form of polished cabochons and beads and increases in value the more vivid its color. Turquoise has a specific gravity of 2.60-2.80 and a hardness of 5-6.
Zircon is not to be confused with cubic zirconia, the synthetic diamond substitute. Zircon is a naturally occurring gemstone, at one time believed to have mystic powers such as the power to heal and increase the wisdom of its wearer. It is found in a range of colors such as red, yellow, orange and green, the most popular being blue. The oldest zircons discovered within meteors are the most ancient substance on earth. It is mined throughout Asia and has a specific gravity of 4.6-4.7 and a hardness of 7.5.