Amethyst (Quartz)

Physical Properties

Hardness: 7 (Mohs scale); Color: Pale violet to deep purple; Luster: Vitreous (glassy); Crystal structure: Trigonal (often found as hexagonal prisms); Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Formation & Geological History

Formed in hydrothermal veins or geodes within volcanic rocks when silica-rich water cools. The purple color is caused by irradiation of iron impurities within the silicon dioxide crystal lattice. Most specimens are found in Cenozoic or Mesozoic era deposits.

Uses & Applications

Primary use is in jewelry, gemstone collecting, and ornamental carvings. It is the birthstone for February and widely used in decorative items like bookends and geodes.

Geological Facts

Amethyst was once considered a 'Cardinal Gem,' ranking alongside Diamond and Sapphire in value until large deposits were found in Brazil. The name comes from the Greek 'amethystos', meaning 'not intoxicated', due to an ancient belief it prevented drunkenness.

Field Identification & Locations

Identify by its distinctive purple hue and hexagonal crystal shape. It can be found in mountain ranges or volcanic regions globally, notably in Brazil, Uruguay, and Canada. In the field, look for purple crystals inside hollow rock cavities (geodes).

Identified on: 4/14/2026

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