Rock Identifier
Amethyst (Silicon Dioxide (SiO2) with iron impurities) — mineral
mineral

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Hardness: 7 on Mohs scale; Color: Purple, violet, or lavender; Luster: Vitreous (glass-like); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness
7 on Mohs scale
Color
Purple, violet, or lavender
Luster
Vitreous (glass-like)
Identified More mineral

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Physical properties

Hardness: 7 on Mohs scale; Color: Purple, violet, or lavender; Luster: Vitreous (glass-like); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Forms in hydrothermal veins and hollow cavities (geodes). The purple color is caused by irradiation, iron impurities, and the presence of trace elements. Found in igneous or metamorphic host rocks.

Uses & applications

Extensively used in jewelry (faceting, beads, cabochons), carvings, as decorative healing crystals, and by mineral collectors.

Geological facts

Amethyst is the birthstone for February. The name comes from the Ancient Greek word 'amethystos', meaning 'not intoxicated', as it was believed to protect the wearer from drunkenness.

Field identification & locations

Identified by its distinctive purple hue and lack of cleavage. It can be found globally with major deposits in Brazil and Uruguay. In the field, look for purple crystals within geode structures or hexagonal prisms.