Mineral Information and Data:

SrSO4 [CNMNC approved formula]

Named from the Latin caelestis - sky (blue). Mineral name has been known since antiquity and predates any formal descriptive publication. For instance, it is mentioned as a sulfate of strontium in: Bras-de-Fer L (1778) (84) Terre (Élément). Name is clarified and approved: International Mineralogical Association (1967) Commission on new minerals and mineral names, Mineralogical Magazine 36, 131-136.

IMA status : Approved Species Ancient (1967)
(8th edition) :  
  (28) Anhydrous Acid and Sulfates
  (28.03) (A++) XO4
  (28.03.01) Barite Group
(10th edition) :
  (07) Sulfates (selenates, tellurates, chromates, molybdates, wolframates)
  (07.A) Sulfates (selenates, etc.) without Additional Anions, without H2O
  (07.AD) With only large cations
Crystal system: Orthorhombic System
Point group (H-M): mmm (or 2/m 2/m 2/m) — dipyramidal
Unit cell: a = 8.359 Ǻ, b = 5.352 Ǻ, c = 6.866 Ǻ
Crystal Habit: Crystals thick to thick tabular, equant, or pyramidal, nodules, fibrous veinlets; massive granular, lamellar, earthy
Color: Colorless, white, blue gray, green, yellow, red, brown
Diaphaneity: Transparent, Translucent
Luster: Vitreous, Pearly
Hardness (Mohs): 3 to 3.5
Measured Density: 3.97 g/cm3
Cleavage: 3; {001} perfect, {210} good, {010} indistinct
Tenacity: Brittle
Fracture: Uneven
Streak: White
Polymorphism and Series: Forms a series with baryte.
Geologic Setting: Of primary sedimentary origin, diagenetic, or typically as fissure and cavity fillings (including caves) precipitated by migrating strontium-bearing ground water or basinal brines in carbonate rocks, concretions and nodules; in hydrothermal veins and mafic volcanic rocks.
Mineral Association: Gypsum, anhydrite, sulfur (bedded evaporites); strontianite, calcite, dolomite,
anhydrite, gypsum, fluorite (cavities in carbonate rocks); analcime, natrolite, hydroxyapophyllite, celadonite (mafic volcanoclastics)
Synonyms/varieties: Celestite, cliftonite (impure var.)
Luminescent Properties: Sometimes fluoresces.
Other Properties: Gemstone Extremely Rare. BioMineral.


Origin: Billie mine, Death Valley, California, United States
Sample size: 4.5 x 3 x 3 cm
Photo: Tom Loomis


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Origin: Holloway Quarry, Newport, Michigan, U.S.A.
Sample size: 10.5 x 9 x 4 cm
Photo: Rob Lavinsky


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Origin: Sakoany Mine, Majunga, Madagascar
Sample size: 17 x 14.5 x 11 cm
Photo: Rob Lavinsky


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