mineral

Amethyst (Rough)

Amethyst (SiO2 with Iron impurities)

Hardness: 7 on Mohs scale; Color: Purple, violet, or lavender; Luster: Vitreous (glassy) when fresh; Crystal structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Purple, violet, or lavender
Luster: Vitreous (glassy) when fresh

Identified July 15, 2026More mineral →

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Physical properties

Formation & geological history

Formed in hydrothermal veins or as linings in geodes. The purple color is caused by irradiation of iron impurities within the quartz structure. Most specimens are found in basaltic rocks or volcanic cavities.

Uses & applications

Primarily used as a gemstone in jewelry, for decorative carvings, and as a popular specimen for mineral collectors. It is also the birthstone for February.

Geological facts

Amethyst was once considered one of the 'Cardinal Gems' along with diamond, ruby, sapphire, and emerald until large deposits were found in Brazil. The name comes from the Ancient Greek 'amethystos', meaning 'not intoxicated'.

Field identification & locations

Identify it by its distinct purple hue and quartz-like hardness (it can scratch glass). Rough specimens often show hexagonal crystal faces or a jagged, glassy fracture. Commonly found in Brazil, Uruguay, and parts of the United States like Arizona and North Carolina.

Other mineral specimens

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Sandstone with Mineral Veining or Crust

Sedimentary Sandstone (mostly SiO2 with Fe2O3 tinting)

sedimentary

Schist

Metamorphic

Potassium Feldspar (Orthoclase)

Orthoclase (KAlSi3O8)

mineral

Gypsum (variety Selenite or Alabaster)

Calcium sulfate dihydrate (CaSO4·2H2O)

Mineral

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic