Topaz

Topaz is a silicate mineral of aluminium and fluorine. It is utilized as a gemstone in jewelry and other mineral carvings. Common topaz in its natural state is colorless, though trace element impurities can make it pale blue, or golden brown to yellow orange. Topaz is often treated with heat or radiation to make it a deep blue, reddish-orange, pale green, pink, or purple.

Formation & Geology

Topaz is commonly associated with silicic igneous rocks of the granite and rhyolite type. It typically crystallizes in granitic pegmatites or in vapor cavities in rhyolite lava flows including those at Topaz Mountain in western Utah and Chivinar in South America. It can be found with fluorite and cassiterite in various areas including the Ural and Ilmen mountains of Russia.

Physical Characteristics

Topaz is a defining mineral of the Mohs hardness scale, possessing a hardness of 8. This hardness combined with its transparency and variety of colors makes it widely used in jewelry. However, it has perfect cleavage, which means it can be split easily in one direction, requiring care when cutting and setting.

Historical Significance

The name 'topaz' is usually derived (via Old French: Topace and Latin: Topazus) from the Greek Τοπάζιος (Topázios) or Τοπάζιον (Topázion), the ancient name of St. John's Island in the Red Sea which was difficult to find and from which a yellow stone (now believed to be chrysolite: yellowish olivine) was mined.

Imperial Topaz & Treatments

The most valuable variety is "Imperial Topaz," which features a rich golden-orange to pinkish-red color. It was named in honor of the Russian Czars. In contrast, the popular blue topaz seen in jewelry stores is almost always produced by irradiating colorless topaz and then heating it. This treatment is stable and permanent, making blue topaz an affordable and beautiful gemstone.