mineral

Amethyst Stalactite Slice

Crystalline Quartz (SiO2) with trace Iron (Fe4+)

Hardness: 7 on Mohs scale; Color: Purple to violet with a central white/yellow core; Luster: Vitreous; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Purple to violet with a central white/yellow core
Luster: Vitreous

Identified June 17, 2026More mineral →

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Physical properties

Formation & geological history

Formed in volcanic cavities or geodes as silica-rich hydrothermal fluids precipitate over thousands of years. Stalactite formations occur when crystals grow around a central point like a hollow tube. Common in Minas Gerais, Brazil and Uruguay.

Uses & applications

Primarily used in jewelry (pendants), ornamental decor, and as metaphysical or collectible specimens.

Geological facts

The purple color is caused by irradiation of iron impurities within the quartz. Amethyst was once considered one of the five cardinal gemstones alongside diamonds and rubies until large deposits were found in South America.

Field identification & locations

Identified by the radial growth pattern around a central core (resembling a flower) and the characteristic purple crystalline edges. It is often sliced thin and polished to reveal the internal structure for use in jewelry.

Other mineral specimens

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral