mineral

Celestite

Celestine (SrSO4)

Hardness: 3-3.5 on Mohs scale. Color: Pale blue, white, colorless, sometimes yellowish or reddish. Luster: Vitreous to pearly. Crystal structure: Orthorhombic. Cleavage: Perfect in three directions. Specific gravity: 3.9-4.0.

Hardness: 3-3
Color: Pale blue, white, colorless, sometimes yellowish or reddish
Luster: Vitreous to pearly

Identified July 31, 2026More mineral →

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Physical properties

Formation & geological history

Formed mainly in sedimentary environments, often in cavities of limestone and sandstone, as well as in evaporite deposits associated with gypsum and halite.

Uses & applications

Primary source of the element strontium, used in pyrotechnics (red fireworks), ceramics, and metallurgy. Also valued as a collector mineral and for decorative display pieces.

Geological facts

Celestite is named from the Latin word caelestis, meaning celestial, in allusion to the occasional delicate blue color of the mineral. Fine crystals are highly sought after by mineral collectors.

Field identification & locations

Can be identified by its distinctive pale blue color, softness (easily scratched by a copper coin), perfect cleavage, and relatively heavy feel due to its high specific gravity. Found worldwide, with notable deposits in Madagascar, Ohio (USA), and Italy.