mineral

Celestite

Strontium Sulfate (SrSO4)

Hardness: 3 - 3.5 on Mohs scale; Color: Pale sky-blue, transparent to translucent; Luster: Vitreous to pearly; Crystal structure: Orthorhombic; Cleavage: Perfect in one direction, good in another; Specific gravity: 3.9 - 4.0

Hardness: 3 - 3
Color: Pale sky-blue, transparent to translucent
Luster: Vitreous to pearly

Identified July 25, 2026More mineral →

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Physical properties

Formation & geological history

Formed primary in sedimentary rocks such as limestones, dolomites, and gypsum deposits through precipitation from strontium-rich low-temperature hydrothermal fluids or evaporating saline water.

Uses & applications

Primary industrial source of strontium used in pyrotechnics (red fireworks), television glass, signal flares, and highly sought after as display specimens and in metaphysical practices.

Geological facts

Named from the Latin word 'coelestis' meaning 'heavenly' or 'celestial' in reference to its delicate sky-blue color. Famous giant geodes of celestite are found in Madagascar and Crystal Cave, Ohio.

Field identification & locations

Identified by its distinctive pale blue color, high density (feels heavy for its size), and soft scratch resistance. Notable locations include Madagascar, Spain, Mexico, and Ohio, USA.