Topaz is a silicate mineral that is valued as a gemstone.
It is a silicate of aluminium and fluorine with the chemical formula Al2SiO4(F, OH)2.
Topaz is one of the hardest naturally occurring minerals (Mohs hardness of 8) and is the hardest of any silicate mineral. This hardness combined with its usual transparency and variety of colors means that it has acquired wide use in jewellery as a cut gemstone as well as for intaglios and other gemstone carvings.
Topaz grows as a crystal mineral in various granite rocks, and in lava flows.
Today, topaz can be found in various areas including the Ural and Ilmen mountains of Russia, in Afghanistan, Sri Lanka, Czech Republic, Germany, Norway, Pakistan, Italy, Sweden, Japan, Brazil, Mexico; Flinders Island, Australia; Nigeria and the United States.
Topaz in its natural state is a golden brown to yellow. A variety of impurities and treatments may make topaz wine red, pale gray, reddish-orange, pale green, or pink (rare), and opaque to translucent/transparent.
Orange topaz, also known as precious topaz, is the traditional November birthstone, the symbol of friendship, and the state gemstone of the US state of Utah.
Imperial topaz is yellow, pink or pink-orange. Brazilian imperial topaz can often have a bright yellow to deep golden brown hue, sometimes even violet. Many brown or pale topazes are treated to make them bright yellow, gold, pink or violet colored. Some imperial topaz stones can fade on exposure to sunlight for an extended period of time. The golden Imperial topaz is the 16th and 23rd anniversary stone.
Blue topaz is the state gemstone of the US state of Texas. Naturally occurring blue topaz is quite rare. Typically, colorless, gray or pale yellow and blue material is heat treated and irradiated to produce a more desired darker blue. Blue topaz symbolizes honesty, clarity of feelings, and deep emotional attachment. The blue topaz is the 4th anniversary stone.
Mystic topaz is colorless topaz which has been artificially coated via a vapor deposition process giving it a rainbow effect on its surface.
In 1750 a Parisian jeweler discovered that the yellow Brazilian topaz becomes pink on exposure to a moderate heat, and this treatment has since been extensively applied, so that nearly all the pink topaz occurring in jewelry has been heat-treated.
The name “topaz” is derived from the Greek topazos, “to seek,” which was the name of an island in the Red Sea that was difficult to find and from which a yellow stone (now believed to be chrysolite: yellowish olivine) was mined in ancient times.
In the Middle Ages the name topaz was used to refer to any yellow gemstone, but now the name is only properly applied to the silicate described above.
Many English translations of the Bible, including the King James Version, mention topaz. However, because these translations as topaz all derive from the Septuagint translation topazi[os], which referred to a yellow stone that was not topaz, but probably chrysolite, topaz is likely not meant here.
The El-Dorado Topaz, which weighs a whopping 31,000 carats (6.2 kg or 13.67 lbs) currently holds the crown as the largest faceted gemstone in the world. Originally discovered in 1984 in mineral-rich Minas Gerais, Brazil, the pre-cut El-Dorado crystal tipped the scales at a mind-boggling 37 kg (81.6 lbs). It belongs to the British Royal Collection.
The American Golden Topaz currently holds the record for the largest piece of cut yellow topaz in the world. It is sized at 22,892 carats (4.5785 kg) and has 172-facets (flat-faced cuts applied to gems, in order to help them reflect light.) The gem was cut from a piece of yellow topaz that was 11.8 kg (26 lb) in size. The original mineral was discovered in the Minas Gerais, Brazil, and cut by Leon Agee over a period of two years. In 1988, the American Golden Topaz was donated to the Smithsonian Institute, and put on display in the National Museum of Natural History in Washington, D.C. The price of the gem remains unclear.