mineral

Amethyst

Silicon Dioxide (Quartz variety), SiO2

Hardness of 7 on the Mohs scale, purple to violet color, vitreous luster, trigonal crystal system, conchoidal fracture with no true cleavage, specific gravity of 2.65.

Identified August 4, 2026More mineral →

Explore Amethyst in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness of 7 on the Mohs scale, purple to violet color, vitreous luster, trigonal crystal system, conchoidal fracture with no true cleavage, specific gravity of 2.65.

Formation & geological history

Formed in hydrothermal veins and gas cavities (vugs/geodes) within volcanic rocks, where silica-rich solutions cool and crystallize over millions of years.

Uses & applications

Widely used in jewelry as a gemstone, decorative carvings, ornamental objects, and holistic crystal collections.

Geological facts

Amethyst was historically considered one of the cardinal gemstones of high value until extensive deposits were discovered in Brazil. Its purple color comes from irradiation and trace amounts of iron impurities.

Field identification & locations

Identified by its characteristic purple color and a hardness of 7 which can easily scratch glass. Commonly found in Brazil, Uruguay, Zambia, and the United States (such as Arizona and North Carolina).