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Download hereGENERAL DESCRIPTION
Celestite is a strontium sulphate. It shows crystals prismatic, orthorhombic, pointing out those of the barite with which it forms a series.
Crystals of blue sky celestite are very appreciated. It is more generally colourless or white and translucent. Celestite can take a yellowish colour if it is in contact with an environment enriched in sulphur.
It can be found in sedimentary deposits, associated with gypsum, calcite and dolomite. Celestite is the principal strontium (Sr) ore, this last element is used in lighting rockets and fireworks of red colour. Although it is the most common mineral containing strontium, there exist only few deposits where beautiful crystals can be found, such as Sakoany in Madagascar, Bell' S Mill, Bellwood, Pennsylvannia, USA and Agrigento in Sicily (Italy).
In France, blueish samples were found in downtown Paris, associated to yellow calcite; small orange crystals at Arignac in Ariège and the beautiful geodes of blue crystals in Remuzat (Drôme).
45 holotypes of this species are kept at the Berkwerk Akademie ("School of the Mines") of Freiberg in Germany. The samples arise from Bellwood in Pennsylvania in USA (wrongfully attributed to Agrigento, Sicily).
HISTORY : Name inspired from the Latin "caelestis" meaning celest
Species first described in 1798 by Abraham Gottlob Werner (1749-1817), German geologist of the Bergwerk Akademie ("School of Mines"), Freiberg, Germany
Type-locality: Bell's Mill, Bellwood, Pennsylvannie, USA
ANCIENT NAME : Strontiane sulfurée
CHEMICAL FORMULA : Sr SO4
CRYSTAL SYSTEM : Orthorhombic
COLOR : Colorless, white, blue ciel, pale green
DIAPHANIETY : Transparent to translucent
LUSTER : Vitreous, pearly
STREAK : White
MORPHOLOGIE : Tabular crystals, bigs, elongated, fibrous, lamellar
HARDNESS : 3,0-3,5
CHEMICAL CLASS: 3,98
DENSITY : VI - Sulfates, chromates, tungstates and molybdates
GROUP : Barite
STRUNZ CLASS BEFORE 2001 : 6/A.09-10
STRUNZ CLASS AFTER 2001 : 7.AD.35
