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Gemstone Education

Gemstone Education

Gemstones A-Z

A free informational reference guide to gemstones

 
Alexandrite
It’s the color-change variety of the mineral, chrysoberyl. Alexandrite is bluish green in daylight and purplish red under incandescent light, hard and durable.
Birthstone month: June.
Amber
A fossilized resin, amber is the color of the burnished sun – orange or golden brown. Sometimes it traps and preserves ancient life, including insects. Amber is the birthstone for the Start Sign of Taurus.
Amethyst
A purple variety of the mineral quartz,  amethyst often forms large, six-sided crystals. The name of the gem comes from a Greek word that means 'not drunk'.
Birthstone month: February.
Citrine
Citrine’s color comes from traces of iron. It’s perhaps the most popular purchased yellow gemstone and an attractive alternative for topaz and yellow sapphire.
Birthstone month: November.
Ametrine
Ametrine, one of the rarest types of transparent quartz, combines two colors: amethyst’s purple and citrine’s orange-to-yellow. It is the birthstone for those born in February and November.
Aquamarine
The aquamarine is blue to a slightly greenish-blue variety of the mineral beryl. Its crystals are sometimes big enough to cut fashioned gems of more than 100 carats.
Birthstone month: March.
Diamond
The hardest gem of all is made of just one element: carbon. A diamond is valued for its colorless nature and purity. Most diamonds are primeval—over a billion years old—and are formed deep within the earth.
Birthstone month: April.
Fancy Color Diamond
Only one in every 10,000 diamonds possesses natural color and is referred to as a fancy color diamond. They are purchased almost exclusively for the intensity and distribution of the diamond's color.
Emerald
Emerald is the most valued variety of beryl. Spanish conquistadors, Inca kings, Moguls, and Pharaohs all desired to possess it. Today, the finest emeralds come from Africa, South America, and Central Asia.
Birthstone month: May.
Garnet
The garnet group of related mineral species offers gems of every hue, including fiery red pyrope, vibrant orange spessartine, and rare intense-green varieties of grossular and andradite.
Birthstone month: January.
Iolite
Known in the jewelry trade as iolite, this mineral is known as cordierite to geologists and mineralogists. Iolite is strongly trichroic, meaning that it shows three colors when viewed from different angles.
Jade
Prized by civilizations from ancient China to the Aztecs and Mayans of Central America, jade is crafted into objects of stunning artistry. It is known for its beauty and wide-ranging expressiveness.
Birthstone month: August.
Kunzite
Trace amounts of manganese give this pink-to-violet variety of spodumene its feminine glow. Kunzite was only confirmed as a unique variety of spodumene in the early part of the twentieth century.
Birthstone month: September.
Lapis Lazuli
Lapis lazuli is a gemstone of the kind that might have come straight out of the Arabian Nights: a deep blue with golden inclusions of pyrites, which shimmer like little stars. Regarded as the stone of friendship and truth, lapis lazuli is an alternate birthstone for those born in December.
Moonstone
Feldspar is prized for its billowy blue adularescence, caused by light scattering from an intergrowth of microscopic, alternating layers. It is the favored gem of many Art Nouveau jewelry designers.
Birthstone month: June.
Morganite
Like its cousins, emerald and aquamarine, morganite is a variety of the beryl mineral species. This gem gets its subtle blush when a trace amount of manganese makes its way into morganite's crystal structure.
Birthstone month: October
Opal
Opal’s microscopic arrays of stacked silica spheres diffract light into a blaze of flashing colors. An opal's color range and pattern help determine its value. Legend says that it is especially good for the eyes.
Birthstone month: October.
Pearl
Pearls are produced in the bodies of marine and freshwater mollusks, either naturally or cultured by people with great care. Lustrous, smooth, subtly colored pearls are jewelry staples, especially as strands.
Birthstone month: June.
Peridot
Peridot is a yellow-green gem variety of the mineral olivine. Found as nodules in volcanic rock, occasionally as crystals lining veins in mountains of Myanmar and Pakistan, and occasionally inside meteorites.
Birthstone month: August.
Rose Quartz
Microscopic mineral inclusions cause the pink color and translucence of rose quartz. Well-shaped, transparent pink quartz crystals are rare. It is an irresistible addition to any jewelry wardrobe.
Ruby
Traces of chromium give this red variety of the mineral corundum its rich color.  The ruby has been long valued by humans of many cultures. In ancient Sanskrit, ruby was called ratnaraj, or 'king of precious stones'.
Birthstone month: July.
Sapphire
Depending on their trace element content, sapphire varieties of the mineral corundum might be blue, yellow, green, orange, pink, purple or even show a six-rayed star if cut as a cabochon.
Birthstone month: September.
Spinel
Although frequently confused with ruby, spinel stands on its own merits. Available in a striking array of colors, its long history includes many famous large spinels still in existence. Birthstone month: August.
Sunstone
Sunstone, a member of the feldspar group, can be orthoclase feldspar or plagioclase feldspar, depending on chemistry. Both can show aventurescence. "Sunstone" applies to the gem's appearance.
Tanzanite
Named for Tanzania, the country where it was discovered in 1967, tanzanite is the blue-to-violet or purple variety of the mineral zoisite. It’s become one of the most popular of colored gemstones.
Birthstone month: December.
Topaz
Colorless topaz treated to blue is a mass-market gem. Fine pink-to-red, purple, or orange gems are one-of-a-kind pieces. Top sources include Ouro Prêto, Brazil, and Russia’s Ural Mountains.
Birthstone month: December.
Tourmaline
Tourmaline's name comes from the Sinhalese word, turmali, which means 'mixed'. Occurring in more colors or combinations of colors than any other gemstone, tourmaline lives up to its name.
Birthstone month: October.
Turquoise
It is rare and valuable in finer grades and has been prized as a gem and ornamental stone for thousands of years owing to its unique hue. Turquoise occurs as veins or seam fillings and as compact nuggets.
Birthstone month: December.
Zircon
Colorless zircon is known for its brilliance and flashes of multicolored light, called fire. These zircon properties are close enough to the properties of diamond to account for centuries of confusion between the two gems.
Birthstone month: December.

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