Celestine (the IMA-accepted name) or celestite is a mineral consisting of strontium sulfate ( SrSO). The mineral is named for its occasional delicate blue color. Celestine and the carbonate mineral
strontianite
Strontianite ( Sr C O3) is an important raw material for the extraction of strontium. It is a rare carbonate mineral and one of only a few strontium minerals. It is a member of the aragonite group.
Aragonite group members: aragonite (CaCO3), ...
strontium
Strontium is the chemical element with the symbol Sr and atomic number 38. An alkaline earth metal, strontium is a soft silver-white yellowish metallic element that is highly chemically reactive. The metal forms a dark oxide layer when it is ex ...
Celestine derives its name from the Latin word ''caelestis'' meaning celestial which in turn is derived from the Latin word ''caelum'' meaning sky or heaven.
Occurrence
Celestine occurs as crystals, and also in compact massive and fibrous forms. It is mostly found in sedimentary rocks, often associated with the minerals gypsum, anhydrite, and halite. On occasion in some localities, it may also be found with
sulfur
Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula ...
inclusions.
The mineral is found worldwide, usually in small quantities. Pale blue crystal specimens are found in Madagascar. White and orange variants also occurred at Yate, Bristol, UK, where it was extracted for commercial purposes until April 1991.
The skeletons of the
protozoan
Protozoa (singular: protozoan or protozoon; alternative plural: protozoans) are a group of single-celled eukaryotes, either free-living or parasitic, that feed on organic matter such as other microorganisms or organic tissues and debris. Histo ...
'' Acantharea'' are made of celestine, unlike those of other radiolarians which are made of silica.
In carbonate marine sediments, burial dissolution is a recognised mechanism of celestine precipitation. It is sometimes used as a gemstone.
Celestine Poland.jpg, Celestine from the Machow Mine, Poland
Celestine SrSO4.jpg, Celestine mineral on display at Yale's Peabody Museum
Geodes
Celestine crystals are found in some geodes. The world's largest known geode, a celestine geode in diameter at its widest point, is located near the village of Put-in-Bay, Ohio, on South Bass Island in Lake Erie. The geode has been converted into a viewing cave, Crystal Cave, with the crystals which once composed the floor of the geode removed. The geode has celestine crystals as wide as across, estimated to weigh up to each.
Celestine geodes are understood to form by replacement of alabaster nodules consisting of the calcium sulfates gypsum or anhydrite. Calcium sulfate is sparingly soluble, but strontium sulfate is mostly insoluble. Strontium-bearing solutions that come into contact with calcium sulfate nodules dissolve the calcium away, leaving a cavity. The strontium is immediately precipitated as celestine, with the crystals growing into the newly-formed cavity.
Celestitemadagascar.jpg, Celestine geode section
Crystal Cave Ohio.JPG, Inside the Crystal Cave geode in Ohio