The blue color of tanzanite is caused by small amounts of vanadium within the zoisite mineral structure. When vanadium-bearing zoisite is heated to a temperature of 600 degrees Celsius for about 30 minutes, the oxidation state of the vanadium is changed and that change causes or improves the blue color. The heat treatment of tanzanite…

The mineral zoisite naturally occurs in a wide range of colors that include colorless, gray, yellow, brown, pink, green, blue, and violet. The name “tanzanite” is used for a color variety of zoisite that ranges from blue, through violet, to violetish purple. This type of color-variety name is not unusual. The name “ruby” is used…

Although nearly all of the world’s most popular gemstones have been known and used for hundreds of years, tanzanite was not discovered in commercial quantities until the 1960s. In the short time since then, it has become the second most popular blue gem after sapphire. It is one of a very small number of gems of any color that have been discovered…

Tanzanite is a trade name that was first used by Tiffany and Company for gem-quality specimens of a mineral named zoisite with a blue color. Tiffany could have sold the material under the mineralogical name of “blue zoisite,” but they thought the name “tanzanite” would stimulate customer interest and be easier to market. The name “tanzanite” was given because…