24 Nisan 2013 Çarşamba

Pennsylvania State Mineral

Pennsylvania State Mineral


Mineral Representative of Pennsylvania
Celestine is a strontium sulfate, sometimes containing traces of barium. Also known as celestite, this is by far the most common mineral containing strontium. In addition to its characteristic and most common pale blue color, celestine also occurs as light gray, white, colorless, orange, yellow, pink, greenish-blue, black, and shades of brown. Celestine is a member of the barite group, forming a series with the mineral barite. Since barite and celestine have the same structure and form very similar crystals, the two appear similar, but a flame test can distinguish them.
Celestine was first discovered in Pennsylvania in the late 18th century by visiting German mineralogists. They brought a specimen back to Germany for analysis and discovered it to be a previously unknown mineral. The collection site was on Brush Mountain, near what is now Bellwood in Blair County, Pennsylvania. The mineral occurred as plates in shaly limestone in the transition between the Silurian Wills Creek and Tonoloway Formations. It is now known to occur in many counties in the state.
The Central Pennsylvania Rock and Mineral Club chose celestine as a candidate for the state mineral, and Pennsylvania schoolchildren initiated a proposal to the state legislature several times. On February 4, 2004, the state house of representatives approved a bill that would make celestine the state mineral. The bill continued to the state senate, but did not get out of committee. Although Pennsylvania does not have an official state mineral, celestine represents the state’s geology and history well.
The name for this mineral comes from the Latin and Greek words for "celestial" or "heavenly," referring to celestine’s frequent sky-blue color.
Mainly found in sedimentary rocks, celestine occurs most often as prisms, fibers, grains, and masses, and also as plates and nodules. This mineral also forms as fillings in geodes. It occurs in association with halite, calcite, fluorite, barite, gypsum, and other minerals. Although fine deposits have been discovered in many localities throughout the world, 96 percent of the world’s celestine comes from just four countries: China, Mexico, Spain, and Turkey.
Since celestine is widespread, only a few localities for fine and large crystals are listed here.
  • United States: near Bellwood, Blair County, Pennsylvania; Crystal Cave, Put-in-Bay, South Bass Island, Ottawa County, Ohio; Clay Center, Ottawa County, Ohio; Cave-in-Rock, Hardin County, Illinois; Scofield quarry, Maybee, Monroe County, Michigan; Adamsville, Lampasas County, Texas
  • Canada: Dundas, Ontario
  • Mexico: near Matehuela, San Luis Potosi; and Musquiz and Ramos Arizpe, Coahuila
  • Italy: Girgenti, Caltanissetta; and elsewhere in Sicily
  • Germany: Konrad mine, near Salzgitter, Lower Saxony
  • United Kingdom: Yate, near Bristol, England
  • Norway: Bamle
  • Egypt: Jebel Mokattem, near Cairo
  • Madagascar: Sakoany, near Mahajanga (Majunga)
Celestine is a primary ore of strontium. For many years, the principal use of strontium was for manufacturing glass for cathode-ray tubes (CRTs). Flat-panel displays, which have replaced TV glass, contain little or no strontium. Today, the most important use for strontium is pyrotechnics and ferrite ceramic magnets, which have a range of industrial applications.
The colors and luster of this mineral, in addition to its tendency to associate with other colorful minerals, make it a favorite among collectors. A particularly famous combination is pale blue celestine formed with bright yellow sulfur.
The largest known celestine crystal was found at Crystal Cave in Put-In-Bay, Ohio, on Lake Erie. It measures 3 feet (1 m) across. At this same location, the largest known celestine geode was also found. It measures 35 feet (10.7 m) in diameter at its widest point.
State Mineral
Geode of Celestine
State Mineral
Celestine Crystals Up Close
State Mineral
Celestine Crystals
State Mineral
Celestine Specimen
Group: Barite Group
Chemical Formula: SrSO4
Crystal Structure: Orthorhombic
Hardness (Mohs): 3-3½
Color: Colorless, shades of light blue, white, reddish, greenish, brownish, greyish; colorless or lightly tinted in transmitted light
Transparency: Transparent, translucent
Luster: Vitreous, pearly
Density: 3.96-3.98 g/cm3
Streak: White
Cleavage: On {001} perfect; on {210} good; on {010} poor. Also reported on {011}
Fracture: Irregular/uneven
Tenacity: Brittle
Some data courtesy of the Mineralogical Society of America
Author: World Trade Press

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