mineral
Amethyst Geode
Silicon Dioxide (SiO2) with iron impurities
Hardness: 7 (Mohs scale), Color: Purple to deep violet, Luster: Vitreous (glassy), Structure: Hexagonal crystal system, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65
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Physical properties
Hardness: 7 (Mohs scale), Color: Purple to deep violet, Luster: Vitreous (glassy), Structure: Hexagonal crystal system, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65
Formation & geological history
Formed within volcanic rocks (basalts) as gas bubbles trap mineral-rich hydrothermal fluids. Over millions of years, crystals grow inward from the cavity walls.
Uses & applications
Predominantly used for ornamental purposes, healing stones, high-end jewelry, and as a staple in mineral collections.
Geological facts
The purple color is the result of irradiation and iron impurities within the quartz crystal lattice. It was once considered as valuable as diamonds until large deposits were found in Brazil.
Field identification & locations
Look for a dull, potato-like exterior (rhyolite or basalt) that sounds hollow when tapped. Crystals are only visible once the geode is cracked or sliced open.
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Mineral/Rock
Banded Gneiss (River Rock/Pebble)
Gneiss (specifically a banded variety often found as a river rock)
Metamorphic Rock
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Green Apatite on Albite
Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]
mineral