mineral

Celestite (Celestine)

Strontium sulfate (SrSO4)

Hardness: 3-3.5 on Mohs scale; Color: Pale blue, colorless, or white; Luster: Vitreous (glassy) to pearly; Crystal Structure: Orthorhombic; Cleavage: Perfect; Specific Gravity: 3.9-4.0.

Hardness: 3-3
Color: Pale blue, colorless, or white
Luster: Vitreous (glassy) to pearly

Identified April 23, 2026More mineral →

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Physical properties

Hardness: 3-3.5 on Mohs scale; Color: Pale blue, colorless, or white; Luster: Vitreous (glassy) to pearly; Crystal Structure: Orthorhombic; Cleavage: Perfect; Specific Gravity: 3.9-4.0.

Formation & geological history

Formed primarily in sedimentary rocks, often within geodes or as precipitates from hydrothermal fluids and evaporite deposits. Most famous specimens are from the Cretaceous period.

Uses & applications

Primary source of Strontium for fireworks (adds red color) and metal alloys. Widely used as a decorative mineral specimen and in metaphysical practices.

Geological facts

Celestite gets its name from the Latin 'caelestis,' meaning celestial or heavenly, referring to its characteristic sky-blue color. The largest celestite geode in the world is located in Ohio, USA, and measures 35 feet across.

Field identification & locations

Identify in the field by its distinctive sky-blue color, high density (heavy for its size), and relatively low hardness. Commonly found in Madagascar, Ohio, and Sicily. Collectors look for well-defined crystalline geodes.