mineral

Blue Celestite

Celestine (SrSO4)

Hardness: 3-3.5 on Mohs scale. Color: Pale blue to white. Luster: Vitreous to pearly. Crystal structure: Orthorhombic. Cleavage: Perfect in one direction, good in another. Specific gravity: 3.9-4.0

Hardness: 3-3
Color: Pale blue to white
Luster: Vitreous to pearly

Identified July 31, 2026More mineral →

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Physical properties

Hardness: 3-3.5 on Mohs scale. Color: Pale blue to white. Luster: Vitreous to pearly. Crystal structure: Orthorhombic. Cleavage: Perfect in one direction, good in another. Specific gravity: 3.9-4.0

Formation & geological history

Formed mainly in sedimentary environments, often in cavities of limestone, sandstone, and evaporite deposits from supersaturated solutions.

Uses & applications

Used primarily as an ore of strontium, in pyrotechnics for red/blue flares, and as a popular mineral specimen for collectors.

Geological facts

Celestite gets its name from the Latin word 'caelestis', meaning celestial, referring to its soft sky-blue color. Fine crystal clusters are notably mined in Madagascar.

Field identification & locations

Easily identified by its pale blue color, tabular crystal habit, and low hardness (scratched by a coin). Commonly found in Madagascar, the USA, and Italy.