Mineral

General Rock and Mineral Collection (Center: Angelite / Blue Anhydrite)

Anhydrite (Calcium Sulfate, CaSO4)

Hardness: 3.5 on Mohs scale; Color: Pale blue to lilac (Angelite), white, or grey; Luster: Vitreous to pearly; Crystal structure: Orthorhombic; Specific Gravity: 2.9–3.0.

Hardness: 3
Color: Pale blue to lilac (Angelite), white, or grey
Luster: Vitreous to pearly

Identified April 28, 2026More mineral →

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Physical properties

Hardness: 3.5 on Mohs scale; Color: Pale blue to lilac (Angelite), white, or grey; Luster: Vitreous to pearly; Crystal structure: Orthorhombic; Specific Gravity: 2.9–3.0.

Formation & geological history

Formed from the dehydration of gypsum in sedimentary evaporite deposits. It occurs in extensive layers in sedimentary basins where large volumes of sea water have evaporated.

Uses & applications

Used in the manufacture of sulfuric acid, soil treatment, and plaster. Polished varieties like 'Angelite' are popular for jewelry, carvings, and metaphysical collecting.

Geological facts

Angelite was first discovered in Peru in 1987. It is essentially gypsum that has lost its water content due to heat or pressure. If exposed to water for too long, it can actually turn back into gypsum.

Field identification & locations

Identify in the field by its distinctive pale blue color (when polished), its 'greasy' or pearly luster, and its soft surface which is easily scratched by a copper coin. Commonly found in Peru, Germany, and Mexico.

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Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Epidote

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

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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