Celestine Chrystal (3) Stones Rocks Raw Minerals Collecting

Celestine Crystals 7.9 gr - cm 2.4 x 1.9 x 1.6 Raw Minerals Stones Rocks for Collection, only a piece, ad in photo.
 

Celestine or Celestite is a mineral consisting essentially of strontium sulphate (SrSO4), bipyramidal rhombic, belonging to the homonymous group.

It has a hardness of 3-3.5 on the Mohs scale and a density of 3.9 g / cm3. It is an important strontium mineral.
It comes from the Latin term caelestis (light blue), referring to the color of the crystals.
The crystalline habit occurs in colorless or slightly bluish tabular crystals, usually in limestone and sedimentary rocks, associated with gypsum, anhydrite, rock salt and sulfur. It is also found with other clothes: prismatic, acicular, lamellar (red, white or blue), fibrous, coarse, massive granular.

Celestine can have hydrothermal origin, in association with galena and blende, or evaporitic sedimentary due to the evaporation of brackish water in association with sulfur, gypsum, aragonite, chlorides and other typical minerals. It can also be found in sedimentary rocks, especially limestone. In the sulphates and in the salt deposits. In magnificent crystallized druze it is found, associated with sulfur, in its deposits in Sicily and Romagna (Italy).
In nature it generally occurs in elongated prismatic crystals, sometimes tabular, colorless or milky white, yellowish, blue, in radiated or parallel, massive or concreted aggregates. Celestine is heavy, semi-hard and brittle. The mineral is weakly soluble in water and acids and colors the flame carmine red. It also exhibits thermoluminescence and is fluorescent under ultraviolet rays in yellow and white-blue.