Blue garnets are the rarest of the garnets and sell for $1.5 million a carat.
Gemstones, also known as precious stones, are composed of rare minerals that have been cut and polished. The more limited the mineral, the rarer and more precious the gemstone. The Gemological Institute of America has no consensus on which stone is the rarest, but all of these gems are beautiful, expensive and scarcely found.
Fancy Red Diamonds
The Red Diamond, also known as the "Fancy Red" is the rarest and most valuable of all the diamonds. Like white diamonds it too is composed of compressed carbon, but its brilliant red color sets it apart. Only diamonds that are pure red with no trace of another color are considered "fancy" diamonds. Fancy diamonds are found in the Argyle Mine in Australia, and only 35 are currently reported. The largest of its kind was discovered by a Brazilian farmer in 1990 and is called the Moussaieff Red. Fancy Diamonds are sold for $2.5 million a carat.
Black Opal
Australia's national gemstone, the black opal is the most valuable of all opals. Its prices compare to those of diamonds reaching up to $500,000 for one stone. Contrary to its name, the black opal is not completely black. It has a solid black or dark gray body colored tone that absorbs specks of white light. When reflected the stone displays a brilliant array of colors.
Painite
Arthur C.D. Pain, a British mineralogist, discovered painite in Burma in 1951. Until 1979 only three crystals were known to exist, making painite the rarest mineral on earth. Composed of oxygen, aluminum, boron, calcium and zirconium painite has a reddish brown color that looks green under UV waves. It is sold for $50,000 to $60,000 a carat.
Musgravite
Musgravite was discovered in 1967 in the Musgrave Region of Australia. It has many qualities similar to taaffeite and is often mistaken for it. Musgravite has a pale olive green, gray, mauve or grayish purple color. Called a "rarity among the rare" by the Gemological Institute of America, musgravite sells for $35,000 a carat. As of 2005 there were only eight reported specimens in the world.
Jeremejevite
Jeremejevite was discovered in Nambia by the Russian mineralogist and engineer Pavel Jeremejev in 1883. As of 2010 the only locations on earth known to have jeremejevite are Cape Cross Nambia and Mt. Soktuj in Russia. Jeremejevite is naturally formed into small obelisk-shaped crystals that are colorless, sky blue, dark blue or pale yellow. Jeremejevite is purchased for $2000 a carat.
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