Celestine
Celestine is a sulfate mineral prized by collectors for its exceptional color range, with notable Chinese occurrences.
Celestine (celestite) is strontium sulfate, a mineral famous for its delicate sky-blue crystals, often lining geodes.
About Celestineextended article
Celestine — also called celestite — is strontium sulfate and the chief ore of strontium. Collectors prize it above all for its soft sky-blue colour, the inspiration for its name (from the Latin caelestis, 'heavenly'), seen at its finest in the crystal-lined geodes of Madagascar.
Identifying celestine
Celestine is moderately soft (3–3.5), with tabular or prismatic crystals, a glassy lustre and colours from pale sky-blue to white, grey and pale orange. It closely resembles barite but is lighter and contains strontium rather than barium — strontium gives a crimson flame test.
Where it is found
The famous blue geodes come from Sakoany in Madagascar; other important occurrences include Ohio and Michigan in the United States (large crystals around Lake Erie), Sicily and the United Kingdom.
For collectors
Saturated sky-blue colour, gemmy transparency and sharp, undamaged crystals — especially crystal-lined geode halves — are the most sought-after.
About Celestine
Celestine is classified as a sulfate mineral in the baryte group and has the chemical formula SrSO₄. It crystallizes in the orthorhombic system and is one of the most visually varied minerals in the collector market. Its combination of structural character and global distribution make it a recognized species in both systematic and aesthetic collections.
Identification & care
Specimens usually show tabular, prismatic; nodular; massive; geodes. Its color range is broad, including colorless, shades of light blue (sky to lavender), white, reddish, greenish, and brownish. The luster is vitreous, pearly, the streak is white, and specimens range from transparent to translucent. The cleavage is perfect on {001}, good on {210}. The fracture is uneven, which aids identification.
Collector context
How it forms
The geological setting for Celestine is typically sedimentary — evaporite deposits, limestone vugs; hydrothermal veins. It is commonly found in association with calcite, gypsum, halite, sulfur, dolomite.
Classic Chinese localities
Documented Chinese occurrences are recorded at Shangbao Mine, among others.
Why collectors care
Celestine is a frequently-sought species in serious collections because its habit is recognizable, its color often strong, and its best examples unmistakable even at a distance. Chinese material has driven much of the recent visual shift in the species — sharper crystals, deeper colors, cleaner matrix.
What affects value
Value in Celestine is assessed, in typical order of weight, against: (1) locality provenance; (2) size relative to the species norm; (3) crystal form and termination sharpness; (4) color saturation and zoning; (5) transparency and internal clarity; (6) matrix quality and aesthetic balance; (7) condition (absence of damage, chips, or repair). Cleaning quality and verified locality documentation act as multipliers across the above.
Naming history
The name Celestine has a specific etymological and historical context — see Mindat's reference entry for provenance details. We have retained naming data at the record level; published prose is paraphrased from factual fields rather than copied from source.
Frequently asked questions
What is Celestine?
Celestine is a sulfate mineral prized by collectors for its exceptional color range, with notable Chinese occurrences.
What is the chemical formula of Celestine?
The chemical formula of Celestine is SrSO4.
What crystal system does Celestine belong to?
Celestine crystallises in the Orthorhombic crystal system.
References & databases
Mindat.org is the world’s largest open mineralogy database. Our descriptions are written independently and fact-checked.