mineral

Tumbled amethyst-bearing quartz

Quartz, SiO₂; purple coloration from iron-related defects and irradiation

AI-generated identification · may be incorrect

Hardness 7 Mohs; translucent lavender-purple and honey-brown zones; vitreous to waxy luster; hexagonal crystal structure, though tumbling removes crystal faces; no cleavage, conchoidal fracture; specific gravity about 2.65.

Identified September 16, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich hydrothermal fluids fill volcanic cavities, commonly with amethyst lining geodes; associated material may include iron-stained quartz or chalcedony. Most commercial specimens formed in Cenozoic volcanic regions, though quartz of this type occurs across many geological ages.

Uses & applications

Used as an inexpensive gemstone, carving and decorative stone, crystal-collecting specimen, and occasional jewelry material; the small tumbled piece has modest commercial value.

Geological facts

Amethyst is the purple variety of quartz, and heating can turn it yellow-orange, producing citrine or ametrine-like material. Color intensity depends on iron content and irradiation.

Field identification & locations

Identify by its glassy luster, hardness, lack of cleavage, conchoidal fracture, and purple quartz appearance; common sources include Brazil, Uruguay, Zambia, and Bolivia. This image may also show iron staining or included chalcedony, so laboratory testing is needed for certainty.