mineral

Amethyst Geode

Amethyst (Silicon Dioxide), Formula: SiO2

Hardness: 7 on Mohs scale; Color: Pale violet to deep purple; Luster: Vitreous (glass-like); Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Pale violet to deep purple
Luster: Vitreous (glass-like)

Identified June 2, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Pale violet to deep purple; Luster: Vitreous (glass-like); Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65.

Formation & geological history

Formed in gas bubbles (vesicles) within volcanic rocks or cavities in sedimentary rocks. As mineral-rich water precipitates silica in these cavities over time, crystals grow inward. Typically formed in the Mesozoic or Cenozoic eras.

Uses & applications

Used extensively in jewelry (faceted gemstones, beads), as interior decor/ornamental pieces, and highly valued by mineral collectors for its aesthetic appeal and purported metaphysical properties.

Geological facts

The purple color is caused by irradiation of iron impurities within the quartz. Amethyst is the birthstone for February and was once considered as valuable as diamonds until large deposits were found in Brazil in the 19th century.

Field identification & locations

Identify in the field by looking for rounded, hollow nodules with a bumpy, cauliflower-like exterior; breaking them open reveals internal crystals. Major sources include Brazil, Uruguay, and Madagascar.

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