mineral

Blue Celestite

Celestine (Strontium Sulfate, SrSO4)

Hardness: 3-3.5 (Mohs scale); Color: Pale blue, colorless, white; Luster: Vitreous to pearly; Crystal structure: Orthorhombic; Cleavage: Perfect basal; Specific gravity: 3.9-4.0

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

Identified May 23, 2026More mineral →

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Physical properties

Hardness: 3-3.5 (Mohs scale); Color: Pale blue, colorless, white; Luster: Vitreous to pearly; Crystal structure: Orthorhombic; Cleavage: Perfect basal; Specific gravity: 3.9-4.0

Formation & geological history

Formed as sedimentary deposits in carbonate rocks like limestone or dolostone through the evaporation of seawater, often found in geodes. It can also occur in hydrothermal veins.

Uses & applications

Primary source of the element strontium, used in pyrotechnics (red fireworks), metal alloys, and electronics. Often used as a decorative specimen or in metaphysical practices.

Geological facts

The name is derived from the Latin word 'caelestis' meaning celestial or heavenly, due to its sky-blue color. Madagascar is home to the world's largest Celestite geode.

Field identification & locations

Identified by its heavy weight relative to its size (high specific gravity), its blue color, and rectangular crystal faces. Common in Madagascar, Sicily, and Ohio, USA.