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Topaz is a naturally occurring silicate mineral of fluorine and aluminum with a chemical formula of Al2SiO4(F,OH)2. Aluminum silicate fluoride hydroxide. It can be many different colors. Blue, yellow, clear, brown, green, and rarely pink. Topaz color is often manipulated using heat and radiation to increase the value of the stone. The fact that it will take a high polish and is very hard makes it popular in jewelry.
Physical Properties of Topaz
It is a very hard mineral an 8 on the MOHs scale. Only Diamond and corundum are harder. It has a prismatic habit and is from the orthorhombic crystal system. The luster of topaz is vitreous and it has a colorless streak. It is transparent to translucent.
It is most commonly colorless or a pale yellow, but can be other colors. Traditionaly blue has been the most desirable because of its rarity in nature.
In the 1960s, there was a two-step method discovered to make colorless topaz blue. It is first irradiated to become brown, then a brown stone is heated to get a stable, blue color. This process almost resembles what happens on the crust of the earth, where a heated stone cannot be distinguished from naturally found ones. Before this development, the blue topaz were rare and expensive.
Across the world, Brazil is the leading source of gem-quality topaz. Minas Gerais is the source of fine orange to yellow crystals that can be faceted. Other principal sources of high-quality topaz include Australia, Mexico, Russia, United States, Myanmar, Germany, Madagascar, and Pakistan.
What Kind of Rocks are Topaz Found in?
Topaz is found in igneous rocks. It is typically found in cavities in granite, rhyolites, high temperature veins, and pegmatite dikes.
Topaz has long been valued as a gemstone. It is used in all kinds of jewelry, rings, necklaces, earrings, and other stones of adornment.
Topaz is the birthstone of November and the state mineral for Utah.
This stone is said to strengthen ones confidence and trust in ones self. This brings a sense of peace and self esteem. It helps us connect with nature and brings a sense of purpose. Topaz brings good fortune.
Chemical formula: Al2SiO4(F,OH)2 Aluminum silicate fluoride hydroxide
Color(s): Blue, yellow, clear, brown, green, and rarely pink
Transparency: transparent, translucent
Crystal system: orthorhombic
Specific Gravity: 3.4 - 3.6
Hardness (Mohs): 8
Cleavage: perfect basal
Fracture: subconchoidal to uneven
Location: Russia, Brazil, and Nigeria, Colorado, Texas, and California.