mineral

Amethyst

Purple quartz, silicon dioxide (SiO₂), colored mainly by iron impurities and irradiation

AI-generated identification · may be incorrect

Mohs hardness 7; typically purple to violet with vitreous luster, translucent to transparent, hexagonal crystal structure, and poor cleavage with conchoidal fracture. Specific gravity is about 2.65.

Identified August 26, 2026More mineral →

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Physical properties

Mohs hardness 7; typically purple to violet with vitreous luster, translucent to transparent, hexagonal crystal structure, and poor cleavage with conchoidal fracture. Specific gravity is about 2.65.

Formation & geological history

Forms when silica-rich hydrothermal fluids fill cavities in volcanic rocks, especially basaltic vesicles; purple coloration develops from iron-bearing defects. Many major deposits formed during Phanerozoic volcanic activity, commonly in geodes.

Uses & applications

Used as a gemstone, ornamental specimen, carvings, and in mineral collections; large drusy or geode specimens have decorative value. It has no major structural or industrial use beyond quartz applications.

Geological facts

Amethyst is the purple variety of quartz and is February’s birthstone. Heating can turn it yellow or orange, producing citrine or ametrine-like material.

Field identification & locations

Identify it by purple quartz crystals, vitreous luster, hardness 7, and lack of obvious cleavage; it commonly occurs lining hollow geodes. Important sources include Brazil, Uruguay, Zambia, Namibia, and Russia.