mineral

Raw amethyst crystal

Amethyst, purple quartz (SiO₂) colored mainly by iron impurities and irradiation

AI-generated identification · may be incorrect

Typically Mohs hardness 7, vitreous luster, white-to-violet-purple color, and hexagonal crystal structure; quartz has indistinct cleavage and conchoidal fracture. This small specimen appears pale violet and partially crystalline.

Identified August 23, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater deposits quartz in cavities of volcanic rocks, with iron producing the purple color; most deposits formed in geologically young to ancient basaltic cavities, commonly during the Mesozoic and Cenozoic. Major sources include Brazil, Uruguay, Zambia, and Mexico.

Uses & applications

Used as a gemstone, ornamental crystal, jewelry material, and mineral-collection specimen; fine transparent crystals can be faceted or polished.

Geological facts

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

Field identification & locations

Identify it by purple coloration, glassy luster, hardness sufficient to scratch glass, and quartz-like crystal faces; distinguish it from fluorite by its greater hardness and lack of prominent cleavage. Commonly found in basalt geodes and hydrothermal veins.