Celestine is a strontium sulfate mineral with the formula SrSO4. This mineral is an attractive mineral that forms in well-shaped crystals with a distinctive soft blue color. Crystals may be a solid color but may also have lighter and darker color zones of blue. While pure Celestine is colorless, various impurities give this mineral a wider range of colors, especially its soft blue color. Colors include blue, white, colorless, orange, orange-brown, light brown, yellow, greenish-blue, gray. Crystals may also be slightly multicolored, with light blue on one end and colorless on the other. Sand Celestine is a variety of Celestine with inclusions of sand, causing the specimen to be brown or grayish in color and opaque.
It is named from the Latin word caelestis meaning celestial, alluding to it typical sky-blue color. The crystal is the principal source of the element strontium, commonly used in fireworks and in various metal alloys. The skeletons of the protozoan Acantharea are made of Celestine, unlike those of other radiolarians which are made of silica.
Celestine is the accepted name by the International Mineral Association and is used worldwide except in the United States. The name is still used in the U.S. It is a member of the Baryte (Barite) group of minerals. This crystal is isomorphous with Barite, meaning that the molecular arrangement is identical, but their specific elements are different.
Composition and Chemistry
Celestine is typically found as prismatic and tabular crystals, and as thin tabular plates. It also occurs in thick, pseudohexagonal trillings, as well as dense aggregates of these crystals. May also be massive, radiating, grainy, nodular, and botryoidal. Additional habits include fibrous masses, as dense clusters of tabular crystals, as fragile, elongated (needles) crystal clusters, as fillings in geodes, and as cleavage fragments. Crystals are sometimes striated, and occasionally contain phantom growths. Celestine 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 inclusions.
These crystals are found in some geodes. The world’s largest known geode, a Celestine geode 35 feet 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. The geode has Celestine crystals as wide as 18 inches across, estimated to weigh up to 300 pounds each.
The crystal belongs to the Orthorhombic Crystal System, Dipyramidal Crystal Class. Hardness is 3-3.5 on the Moh’s Scale. Luster can be vitreous, pearly on cleavage surfaces. It can be transparent but usually translucent or opaque. Celestine may occasionally fluoresce yellow in shortwave ultraviolet light. It may be thermoluminescent (emits light after being heated).
Noteworthy Localities of Celestine
Fine Celestine specimens have been obtained from many localities worldwide. Blue and white crystals are found in Italy associated with bright yellow sulfur crystals in the famous Sicilian mines of Cattolico, Agrigento, Floristella, and Caltanissetta. Another locality of Celestine associated with sulfur is the Machow Mine, Tarnobrzeg, Poland.
Several important localities in Spain are Puente Tablas, in Andalusia; Tora, in Catalonia; and Arneva, in Alicante. White and orange crystals occurred at Yate in Gloucester, England, where it was extracted for commercial purposes until April 1991. Beineu-Kyr, Turkmenistan, is an uncommon yet desirable source of Celestine in the form of tabular and platy white crystals with red inclusions.
Enormous blue Celestine crystals, some in geodes, are found in Madagascar, in Sakoany, Mahajanga Province. Red Celestine which at one time was thought to be Barite comes from the Hammam-Zriba Mine, Tunisia. Other African localities are Jabal Akhdar, Libya; and the Wessels Mine, Hotazel, South Africa.
In North America
Within Canada, Celestine comes from the Lafarge Quarry, Dundas; and from the Deforest Quarry, Inglewood, both in Ontario. In Mexico, Celestine is found in the Mojina Mine, Ahumada, Chihuahua; and in the Tule Mine, Melchor Múzquiz, Coahuila.
Some of the best specimens of Celestine mineral are from the United States. The type locality and earliest occurrence is Bell’s Mill, Bellwood, Blair County, Pennsylvania, where it was found in fibrous veins. Another important Pennsylvania locality is the Meckley’s Quarry, Mandata, Northumberland County. A historic Celestine occurrence is Lockport, Niagara County, New York, where this mineral was discovered while digging the Erie Canal. There are several other Celestine localities in central New York, especially Chittenango Falls, Madison County; and Walworth, Wayne County.
The state of Ohio contains perhaps the greatest deposits. Especially of note is South Bass Island in Lake Erie, where giant pale blue crystals were obtained in the hamlet of Put-in-Bay. Also in Ohio are Lime City, Portage, and the Pugh Quarry, all in Wood County; and Clay Center, Ottawa County, where the Celestine occurs with pale brown Calcite and Fluorite.
Michigan contains well-known Celestine deposits in the Maybee and Scofield Quarries (near Maybee), and at the Newport Quarry, Monroe County. Other U.S. occurrences are the Annabel Lee mine, Hardin County, Illinois; Bull Creek, Austin, Travis County, Texas; and Death Valley, Inyo County, California, where it occurs as large, colorless crystals associated with Colemanite in geodes. Celestine in geodes is also found in the Summerville and Curtis Formations, Emery and Wayne Counties, Utah.
By Bill Jones, Sidewinder Minerals