mineral

Tumbled dark purple mineral, likely amethyst or purple fluorite

Amethyst: quartz (SiO₂); alternative: fluorite (CaF₂)

AI-generated identification · may be incorrect

Small rounded, polished specimen with dark violet color and vitreous luster. Amethyst has Mohs hardness 7, no cleavage, and hexagonal quartz structure; fluorite has hardness 4, prominent cubic cleavage, and cubic structure.

Identified September 4, 2026More mineral →

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Physical properties

Formation & geological history

Amethyst forms when iron-bearing quartz crystallizes in volcanic cavities, commonly during hydrothermal activity; fluorite forms in hydrothermal veins. A precise age and identification require hardness, streak, and magnified examination.

Uses & applications

Used as a low-cost gemstone, ornamental tumbled stone, and collector specimen; amethyst is also used in jewelry and décor, while fluorite is an industrial source of fluorine.

Geological facts

Amethyst’s purple color results mainly from iron-related defects altered by natural radiation. Strongly cubic cleavage or easy scratching suggests fluorite rather than quartz.

Field identification & locations

Common sources include Brazil, Uruguay, Mexico, Zambia, and the United States. Test cautiously: quartz scratches glass, whereas fluorite does not; avoid destructive tests on valuable pieces.