mineral

Celestite (Celestine)

Strontium Sulfate (SrSO4)

Hardness: 3-3.5 on Mohs scale. Color: Pale blue, white, or colorless. 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, white, or colorless
Luster: Vitreous (glassy) to pearly

Identified February 21, 2026More mineral →

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Physical properties

Formation & geological history

Formed primarily in sedimentary rocks, such as limestone and sandstone, as a precipitate from hydrothermal fluids or through the evaporation of alkaline waters. Can also be found in geodes. Most famous deposits are from the Sakoany Mine in Madagascar.

Uses & applications

Primary source of the element strontium, used in pyrotechnics (to create red fire), metal alloys, and glass manufacturing. Also highly popular as a decorative metaphysical stone and mineral specimen for collectors.

Geological facts

The name is derived from the Latin 'caelestis', meaning 'celestial' or 'heavenly', referring to its sky-blue color. It is chemically related to Barite. Large geodes found in Ohio are known as the Crystal Cave, containing some of the largest celestite crystals in the world.

Field identification & locations

Identify by its sky-blue hue, high density relative to its size (heaviness), and brittle nature. It is often found in Madagascar, Sicily, and Tunisia. Collectors should look for its distinct tabular crystal shapes and soft blue clarity.