gemstone

Amethyst

Quartz, silicon dioxide (SiO₂), colored purple by trace iron and irradiation

AI-generated identification · may be incorrect

Purple, transparent-to-translucent crystal with vitreous luster; Mohs hardness 7, trigonal crystal structure, and no true cleavage. The small stone appears cut or polished, so its natural crystal form is not visible.

Identified September 24, 2026More gemstone →

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Physical properties

Formation & geological history

Amethyst forms in silica-rich fluids, commonly lining cavities in volcanic rocks; many deposits are millions to hundreds of millions of years old. This photograph does not establish the stone’s source or age.

Uses & applications

Used in jewelry, ornaments, and mineral collections; it is also used as a decorative stone.

Geological facts

Amethyst is the purple variety of quartz, and its color can fade with prolonged heating or strong sunlight.

Field identification & locations

Identify it by its purple color, glassy luster, and hardness; common sources include Brazil, Uruguay, Zambia, and Madagascar. Confirming a small cut stone’s identity may require gemological testing.