mineral

Celestite (Celestine)

Strontium sulfate (SrSO4)

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

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

Identified May 9, 2026More mineral →

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Physical properties

Formation & geological history

Formed typically in sedimentary rocks as geodes, veins, or replacement linings. It often precipitates from seawater or is concentrated in hydrothermal fluids within limestone or sandstone cavities.

Uses & applications

Primary source of the element strontium, which is used in fireworks (for red colors), metal alloys, and cathode ray tubes. High-quality specimens are popular for metaphysical use and geological collecting.

Geological facts

Its name is derived from the Latin word 'caelestis' meaning celestial or heavenly, referring to its characteristic sky-blue color. Madagascar is world-famous for producing massive pale-blue geodes.

Field identification & locations

Identify by its sky-blue tint, high density (heavy for its size), and poor resistance to scratching. Common locations include Madagascar, Sicily, and Ohio (Lake Erie regions).