mineral

Tumbled amethyst

Quartz, SiO₂; purple variety colored mainly by trace iron and irradiation

AI-generated identification · may be incorrect

Mohs hardness 7; translucent lavender-purple color, vitreous luster, and conchoidal fracture. It has a trigonal crystal structure but no cleavage; specific gravity is about 2.65.

Identified August 11, 2026More mineral →

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Physical properties

Mohs hardness 7; translucent lavender-purple color, vitreous luster, and conchoidal fracture. It has a trigonal crystal structure but no cleavage; specific gravity is about 2.65.

Formation & geological history

Forms when iron-bearing silica-rich fluids fill cavities in volcanic rocks, especially basaltic lava flows; crystals commonly developed during the Cenozoic, though deposits range widely in age.

Uses & applications

Used as a gemstone, ornamental tumbled stone, beads, and mineral-collection specimen; high-quality transparent material is faceted for jewelry.

Geological facts

Amethyst is February’s birthstone and is the purple form of quartz. Heat can turn it yellow-orange, producing citrine-like material.

Field identification & locations

Identify it by its purple quartz appearance, glassy luster, hardness, and lack of cleavage; common sources include Brazil, Uruguay, Zambia, and Morocco. A scratch test with steel should not mark it, though testing is best avoided on finished pieces.