Amethyst (Tumbled)

Physical Properties

Hardness: 7 (Mohs scale), Color: Purple to violet tones with white quartz banding, Luster: Vitreous (glassy), Crystal structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65

Formation & Geological History

Formed in hydrothermal veins or as linings in volcanic geodes (vugs). The purple color results from gamma irradiation and the presence of trace iron replacing silicon in the quartz lattice.

Uses & Applications

Predominantly used for jewelry, lapidary arts, decorative items, and as a popular specimen for collectors and metaphysical use.

Geological Facts

Until the discovery of large deposits in Brazil in the 18th century, amethyst was as expensive as diamonds and rubies. It is the birthstone for February.

Field Identification & Locations

Identify by its distinctive purple hue and lack of cleavage. In the field, it is often found in basaltic rocks as crystal-lined geodes. Tumbled pieces like these are distinguished by their smooth, polished surface and internal zoning.

Identified on: 4/13/2026

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