mineral

Celestite

Celestite (SrSO4)

AI-generated identification · may be incorrect

Hardness: 3 - 3.5 on Mohs scale. Color: Pale sky blue, white, colorless, or yellowish. Luster: Vitreous to pearly on cleavages. Crystal structure: Orthorhombic. Specific gravity: ~3.9 - 4.0. Cleavage: Perfect on {001} and good on {210}.

Hardness: 3 - 3
Color: Pale sky blue, white, colorless, or yellowish
Luster: Vitreous to pearly on cleavages

Identified July 26, 2026More mineral →

Explore Celestite in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Forms as crystals in geodes, nodules, and sedimentary rocks like limestone and dolomite, often as a primary precipitate from evaporated seawater or low-temperature hydrothermal fluids.

Uses & applications

Primary source of strontium used in pyrotechnics (red flames), signal flares, television glass, and metallurgy. Popular among gemstone collectors and metaphysical enthusiasts.

Geological facts

Its name comes from the Latin word 'caelestis', meaning 'heavenly' or 'celestial', referring to its characteristic delicate sky-blue color.

Field identification & locations

Identified by its delicate pale blue color, high specific gravity (feels heavy for its size), and soft, brittle orthorhombic crystals. Major sources include Madagascar, Spain, Mexico, and Ohio, USA.