Celestine
Image: Robert M. Lavinsky (CC BY-SA 3.0)
Mineral NameCelestine
Chemical FormulaSrSO₄
Mohs Hardness3
Crystal Systemorthorhombic
Lustervitreous
Streak Colorwhite
Cleavageperfect on {001}, good on {210}, imperfect on {010}
Fractureuneven
Specific Gravity3.97
Colorspale blue, white, colorless
Transparencytransparent
Type LocalityWessels Mine, Hotazel, Kalahari manganese fields, Northern Cape Province, South Africa
Mineral GroupSulfates
Usessource of strontium, pyrotechnics, ceramics, collector
Associated Mineralsgypsum, anhydrite, halite, sulfur, calcite, dolomite
Raritycommon
Description
The image displays a cluster of pale blue, well-formed celestine crystals, exhibiting a vitreous luster and good transparency. The crystals are typically tabular to prismatic.
Geological Context
Celestine commonly forms in sedimentary rocks, particularly in evaporite deposits, limestones, and dolomites, often as a result of diagenetic replacement or precipitation from hydrothermal solutions.
