mineral

Celestine (or Celestite)

Strontium sulfate (SrSO4)

AI-generated identification · may be incorrect

Hardness of 3 to 3.5 on the Mohs scale. Typically pale blue, white, or colorless. Vitreous to pearly luster. Orthorhombic crystal structure. Perfect cleavage. High specific gravity around 3.95.

Identified September 19, 2026More mineral →

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Physical properties

Hardness of 3 to 3.5 on the Mohs scale. Typically pale blue, white, or colorless. Vitreous to pearly luster. Orthorhombic crystal structure. Perfect cleavage. High specific gravity around 3.95.

Formation & geological history

Forms in sedimentary rocks, particularly dolomites and dolomitic limestones, often as geodes or nodules. Also found in hydrothermal veins and cavities in volcanic rocks.

Uses & applications

Primary source of the element strontium, used in fireworks and flares for its red flame, and historically in sugar beet refining. Popular among mineral collectors for its delicate blue color and crystal formations.

Geological facts

The name comes from the Latin word 'caelestis', meaning celestial, referring to the sky-blue color of some specimens. The largest known geode in the world is a celestine geode located in Put-in-Bay, Ohio.

Field identification & locations

Identified by its pale blue color, high specific gravity (feels heavy for its size), and relatively low hardness (can be scratched by a penny). Common locations include Madagascar, Mexico, and the USA (Ohio, Michigan).