Witherite is a barium carbonate mineral, bariumcarbonoxygen3, in the aragonite group.[ Witherite crystallizes in the orthorhombic system and virtually always is Crystal twinning.][ The mineral is colorless, milky-white, grey, pale-yellow, green, to pale-brown. The specific gravity is 4.3, which is high for a translucent mineral.]
Witherite forms in low-temperature hydrothermal environments. It is commonly associated with fluorite, celestine, galena, barite, calcite, and aragonite. Witherite occurrences include: Cave-in-Rock, Illinois, US; Pigeon Roost Mine, Glenwood, Arkansas, US; Settlingstones Mine Northumberland; Alston Moor, Cumbria; Anglezarke, Lancashire and Burnhope,[Ashburn, J.H., Mining Witherite in North-West Durham, Colliery Guardian, August 1963 (at Durham Mining Museum web-site)] County Durham, England; Thunder Bay area, Ontario, Canada, Germany, and Poland (Tarnowskie Góry and Tajno at Suwałki Region).
Witherite was named after William Withering (1741–1799) an England physician and naturalist who in 1784 published his research on the new mineral. He could show that barite and the new mineral were two different minerals.
Discovery
In 1789 the German geologist Abraham Gottlob Werner named the mineral witherite in honour of William Withering.
Risk to human health
The 18th-century naturalist Dr. Leigh recorded its Lethality effects after the death of a farmer's wife and child. James Watt Jnr. experimented with the mineral on animals and he recorded the same lethal properties.[The Mining Magazine, March 1963, Vol 108, pages 133–139]
Industrial use
An experiment conducted by Josiah Wedgwood, led to it being used in his 'Jasper ware'; the mineral had previously been considered as worthless.[
Witherite has been used for hardening steel, and for making cement, glass, enamelware, soap, dye and explosives.]['Looking Back' p10 Hexham Courant 10 January 2014 featuring a photograph of Settlingstones miners in 1905]
Witherite crystallizes in the orthorhombic system. The are invariably twinned together in groups of three, giving rise to pseudo-hexagonal forms somewhat resembling bipyramidal crystals of quartz, the faces are usually rough and striated horizontally.
Witherite-216507.jpg|Two sharp pseudohexagonal crystals of witherite on calcite from Hardin County, Illinois (size: 6.4 × 5.4 × 3.4 cm)
Witherite-65711.jpg|Witherite crystal from the Cave-in-Rock Sub-District, Illinois – Kentucky Fluorspar District, Hardin County, Illinois
See also
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List of minerals
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List of minerals named after people
External links
