mineral

Amethyst Geode

Silicon Dioxide (SiO2) - Amethyst variety of Quartz

Hardness: 7 (Mohs); Color: Pale lavender to deep violet crystals on a grey/green matrix; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (rhombohedral); Cleavage: None; Specific Gravity: 2.65.

Hardness: 7 (Mohs)
Color: Pale lavender to deep violet crystals on a grey/green matrix
Luster: Vitreous (glassy)

Identified April 14, 2026More mineral →

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Physical properties

Formation & geological history

Formed in hollow cavities (vugs) within volcanic rock through hydrothermal action. Siliceous water seeps into gas bubbles and deposits quartz crystals over thousands of years. Often found in basaltic rocks from the Cretaceous period.

Uses & applications

Used primarily for jewelry, ornamental decor, gemstone collection, and metaphysical practices.

Geological facts

The purple color in Amethyst is caused by irradiation, iron impurities, and the presence of trace elements. It was once considered as valuable as diamonds until large deposits were found in Brazil.

Field identification & locations

Identify in the field by looking for dull, round nodules that feel heavier than they look; when cracked open, they reveal a crystal-lined interior. Common in Brazil, Uruguay, and volcanic regions of Arizona.

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