Topaz is a silicate mineral of aluminium and fluorine with the chemical formula Al2SiO4(F, OH)2. Topaz crystallizes in the orthorhombic system, and its crystals are mostly prismatic terminated by pyramidal and other faces. It 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 jewelry as a cut gemstone as well as for intaglios and other gemstone carvings.
Topaz Mountain is a summit in the Thomas Range of Utah, east of the Thomas caldera. The summit and surrounding area are known for their abundances of semiprecious minerals including topaz, red beryl and opal.
Topaz Mountain is part of the Thomas Range in Juab County, Utah, approximately 36 miles Northwest of Delta, Utah. It lies on publicly owned land managed by the Bureau of Land Management.