The célestine is a Minéral composed of natural sulfate of Strontium (SrSO₄), crystallizing in the crystalline Système orthorbombic, Groupe of space Pbnm .

Often blue sky (or pale) but sometimes colorless, yellowish, reddish… the céléstine is the only mineral one extracted for the production from salts of Strontium, which are used in the sugar industry and for the production of artificial fires, in the form of Sr (NaNO₃) ₂. The célestine gives complete Isomorphisme with the Barytine, but solid solution is limited with the Anhydrite to ordinary temperature.

Frequent in the Calcareous S and the sandstone, where it is associated with Calcite, Dolomite, Gypse, Halite, Soufre, Fluorine.