Amethyst (Agate/Chalcedony variety)

Physical Properties

Hardness: 7 (Mohs scale); Color: Purple/Violet; Luster: Vitreous to waxy; Crystal Structure: Hexagonal (Trigonal); Cleavage: None; Specific Gravity: 2.65

Formation & Geological History

Formed in volcanic cavities (geodes) or hydrothermal veins via crystallization from silica-rich fluids. The purple color is caused by trace amounts of iron influenced by natural irradiation.

Uses & Applications

Primary use is in jewelry (cabochons, faceted stones), ornamental carvings, and as a popular collector's mineral.

Geological Facts

Amethyst is the birthstone for February. Ancient Greeks believed wearing it could prevent intoxication. This specific specimen appears to be a high-dome cabochon, possibly dyed agate depending on the color uniformity.

Field Identification & Locations

Identify by its hardness (scratches glass), purple hue, and lack of cleavage. Common in Brazil, Uruguay, and Namibia. In the field, look for hexagonal crystal points or agate banding in host rock.

Identified on: 4/29/2026

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