mineral

Celestite Geode

Strontium Sulfate (SrSO4)

Hardness of 3 to 3.5 on the Mohs scale, typically pale blue, white, or colorless, vitreous to pearly luster, orthorhombic crystal system, perfect cleavage in three directions, specific gravity around 3.9 to 4.0.

Identified July 30, 2026More mineral →

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Physical properties

Formation & geological history

Forms primarily in sedimentary rocks such as limestones and dolostones, often as cavity-fillings or nodules, precipitated from strontium-rich aqueous solutions over millions of years.

Uses & applications

Used mainly as a mineral specimen for collectors, in the extraction of strontium for pyrotechnics and ceramics, and occasionally carved into ornamental objects.

Geological facts

Celestite gets its name from the Latin word 'caelestis,' meaning celestial, due to its delicate sky-blue color. Madagascar produces some of the finest, largest, and most intensely blue celestite crystal clusters in the world.

Field identification & locations

Can be identified in the field by its distinct pale blue color, high density (heavy feel for its size), and characteristic tabular or prismatic orthorhombic crystal formations inside geodes. Commonly found in Madagascar, Italy, Spain, and the United States.