Celestite
Image: <a rel="nofollow" class="external text" href="https://www.flickr.com/people/14730981@N08">James Petts</a> from London, England (CC BY-SA 2.0)
Mineral NameCelestite
Chemical FormulaSrSO4
Mohs Hardness3
Crystal Systemorthorhombic
Lustervitreous
Streak Colorwhite
CleavagePerfect on {001}, good on {210}, imperfect on {010}
Fractureuneven
Specific Gravity3.96
Colorswhite, pale blue, colorless, pink, yellowish, reddish
Transparencytranslucent
Type LocalityMadagascar, Ohio (USA), Sicily (Italy)
Mineral GroupSulfates
Usesstrontium source, fireworks, pyrotechnics, collector's item
Associated Mineralscalcite, gypsum, sulfur, dolomite
Raritycommon
Description
This specimen displays massive, white to pale blue-grey celestite with a fibrous or platy texture, showing some reddish-orange staining and embedded in a darker, possibly greyish matrix.
Geological Context
Celestite commonly forms in sedimentary rocks, particularly in evaporite deposits, limestones, and dolomites, often as a result of diagenetic replacement or precipitation from low-temperature hydrothermal solutions.
