gemstone

Polished amethyst quartz

Quartz, SiO₂; purple coloration from trace iron and irradiation

AI-generated identification · may be incorrect

Mohs hardness 7; translucent white to lavender-purple, with a vitreous luster and typically no visible cleavage. Hexagonal crystal structure; specific gravity about 2.65, though this specimen is cut and polished.

Identified September 20, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when silica-rich hydrothermal fluids fill cavities in volcanic rocks, commonly basalt, where quartz crystals grow over millions of years. The pictured piece is human-cut from amethyst-bearing quartz.

Uses & applications

Used as a decorative gemstone, cabochon, carving material, and collector specimen; also sold for ornamental and metaphysical purposes. It is less commonly used industrially than ordinary quartz.

Geological facts

Amethyst is the purple variety of quartz; heating can turn it yellow-orange, producing citrine. Color commonly occurs in bands or zones, and pale material may be marketed as “chevron” or “lavender” amethyst when combined with milky quartz.

Field identification & locations

Identify it by purple zoning, glassy luster, hardness sufficient to scratch glass, and lack of cleavage; fluorite and glass are softer. Common sources include Brazil, Uruguay, Zambia, Bolivia, and Mexico.