mineral

Celestite (Celestine)

Strontium Sulfate (SrSO4)

Hardness: 3 - 3.5 on Mohs scale. Color: Pale blue, white, translucent grayish blue. Luster: Vitreous to pearly on cleavage faces. Crystal system: Orthorhombic. Cleavage: Perfect in one direction, distinct in another. Specific gravity: 3.9 - 4.0.

Hardness: 3 - 3
Color: Pale blue, white, translucent grayish blue
Luster: Vitreous to pearly on cleavage faces

Identified July 26, 2026More mineral →

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Physical properties

Formation & geological history

Formed in sedimentary rocks such as gypsum, anhydrite, and limestone, or in hydrothermal veins and cavities. It precipitates from aqueous solutions containing high concentrations of strontium and sulfate.

Uses & applications

Used as the primary ore for strontium, which is utilized in fireworks for red flames, glass manufacture, and metallurgy. Also popular as a tumbled gemstone, collector specimen, and in crystal healing practices.

Geological facts

The name Celestite is derived from the Latin word 'coelestis', meaning 'celestial' or 'heavenly', referring to its characteristic soft sky-blue color. Madagascar is world-famous for producing large geodes filled with fine blue celestite crystals.

Field identification & locations

Identified by its delicate sky-blue hue, relatively high density (heavy for a non-metallic mineral), and soft hardness (easily scratched by copper or steel). Commonly found in Madagascar, Ohio and Michigan (USA), England, and Mexico.