Mineral

Amethyst

SiO2 (Silicon Dioxide) - a variety of Quartz

Hardness: 7 on the Mohs scale. Color: Pale lilac to deep purple, often transparent to translucent. Luster: Vitreous (glassy). Crystal Structure: Hexagonal (trigonal system). Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.

Hardness: 7 on the Mohs scale
Color: Pale lilac to deep purple, often transparent to translucent
Luster: Vitreous (glassy)

Identified September 11, 2025More mineral →

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Physical properties

Formation & geological history

Amethyst forms in hydrothermal veins and vugs (cavities) within igneous rocks, particularly basaltic lavas. The purple color is due to irradiation of iron impurities within the quartz lattice. Geological Age: Varies widely, depending on the host rock, but typically formed during the cooling and crystallization of magmatic fluids.

Uses & applications

Amethyst is a popular gemstone used extensively in jewelry (rings, necklaces, earrings). Larger specimens are valued by collectors and used as decorative pieces. Industrially, quartz in general is used in electronics and optics, but amethyst's primary use is ornamental due to its color.

Geological facts

The name 'amethyst' comes from the Greek word 'amethystos', meaning 'not drunk', as ancient Greeks believed it protected against intoxication. It is the birthstone for February. Large geodes lined with amethyst crystals are a common and impressive sight.

Field identification & locations

Identification in the field: Look for its distinctive purple color, glassy luster, and hardness (it can scratch glass and steel). It often forms in crystal clusters or as druzy coatings within cavities. Common locations: Brazil (known for large geodes), Uruguay, Canada, Siberia (Russia), Zambia, and parts of the United States (e.g., Arizona, North Carolina).

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Epidote - Ca2(Al2,Fe3+)3(SiO4)3(OH)

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