Witherite

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Witherite
Witherite-48305.jpg
Witherite from Alston Moor District, Cumbria, England
General
Category Carbonate mineral
Formula
(repeating unit)
BaCO3
IMA symbol Wth [1]
Strunz classification 5.AB.15
Crystal system Orthorhombic
Crystal class Dipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m)
Space group Pmcn
Unit cell a = 5.31  Å, b = 8.9 Å
c = 6.43 Å; Z = 4
Identification
ColorColorless, white, pale gray, with possible tints of pale-yellow, pale-brown, or pale-green
Crystal habit Striated short prismatic crystals, also botryoidal to spherical, columnar fibrous, granular, massive.
Twinning On {110}, universal
Cleavage Distinct on {010} poor on {110}, {012}
Fracture Subconchoidal
Mohs scale hardness3.0–3.5
Luster Vitreous, resinous on fractures
Streak White
Diaphaneity Subtransparent to translucent
Specific gravity 4.3
Optical propertiesBiaxial (−)
Refractive index nα = 1.529 nβ = 1.676 nγ = 1.677
Birefringence δ = 0.148
2V angle Measured: 16°, calculated: 8°
Dispersion Weak
Ultraviolet fluorescence Fluorescent and phosphorescent, short UV=bluish white, long UV=bluish white
References [2] [3] [4] [5]

Witherite is a barium carbonate mineral, Ba C O 3, in the aragonite group. [2] Witherite crystallizes in the orthorhombic system and virtually always is twinned. [2] 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. [2] It fluoresces light blue under both long- and short-wave UV light, and is phosphorescent under short-wave UV light. [2]

Contents

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, [6] 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 English 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. [4] [7]

Discovery

In 1789 the German geologist Abraham Gottlob Werner named the mineral witherite in honour of William Withering. [8] The Matthew Boulton mineral collection of Birmingham Museum and Art Gallery may contain one of the earliest known specimens of witherite. A label in Boulton's handwriting, records: "No.2 Terra Ponderosa Aerata, given me by Dr. Withering". [9]

Risk to human health

The 18th-century naturalist Dr. Leigh recorded its lethal 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. [10] Until the 18th century farmers at Anglezarke used the mineral as rat poison. [11]

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. [11] Witherite has been used for hardening steel, and for making cement, glass, enamelware, soap, dye and explosives. [12]

Witherite crystallizes in the orthorhombic system. The crystals 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. [13] It transforms into an hexagonal phase at 1084 K that changes into a cubic phase at 1254 K. The mineral is named after William Withering, who in 1784 recognized it to be chemically distinct from barytes. [14] It occurs in veins of lead ore at Hexham in Northumberland, Alston in Cumbria, Anglezarke, near Chorley in Lancashire and a few other localities. Witherite is readily altered to barium sulfate by the action of water containing calcium sulfate in solution and crystals are therefore frequently encrusted with barytes. It is the chief source of barium salts and is mined in considerable amounts in Northumberland. It is used for the preparation of rat poison, in the manufacture of glass and porcelain, and formerly for refining sugar. [13] It is also used for controlling the chromate to sulfate ratio in chromium electroplating baths. [15]

See also

Related Research Articles

<span class="mw-page-title-main">Barium</span> Chemical element, symbol Ba and atomic number 56

Barium is a chemical element; it has symbol Ba and atomic number 56. It is the fifth element in group 2 and is a soft, silvery alkaline earth metal. Because of its high chemical reactivity, barium is never found in nature as a free element.

<span class="mw-page-title-main">Calcium</span> Chemical element, symbol Ca and atomic number 20

Calcium is a chemical element; it has symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to its heavier homologues strontium and barium. It is the fifth most abundant element in Earth's crust, and the third most abundant metal, after iron and aluminium. The most common calcium compound on Earth is calcium carbonate, found in limestone and the fossilised remnants of early sea life; gypsum, anhydrite, fluorite, and apatite are also sources of calcium. The name derives from Latin calx "lime", which was obtained from heating limestone.

<span class="mw-page-title-main">William Withering</span> English scientist

William Withering FRS was an English botanist, geologist, chemist, physician and first systematic investigator of the bioactivity of digitalis.

<span class="mw-page-title-main">Alkaline earth metal</span> Group of chemical elements

The alkaline earth metals are six chemical elements in group 2 of the periodic table. They are beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra). The elements have very similar properties: they are all shiny, silvery-white, somewhat reactive metals at standard temperature and pressure.

<span class="mw-page-title-main">Fluorite</span> Mineral form of calcium fluoride

Fluorite (also called fluorspar) is the mineral form of calcium fluoride, CaF2. It belongs to the halide minerals. It crystallizes in isometric cubic habit, although octahedral and more complex isometric forms are not uncommon.

<span class="mw-page-title-main">Calcite</span> Calcium carbonate mineral

Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on the Mohs scale of mineral hardness, based on scratch hardness comparison. Large calcite crystals are used in optical equipment, and limestone composed mostly of calcite has numerous uses.

<span class="mw-page-title-main">Baryte</span> Barium sulfate mineral

Baryte, barite or barytes ( or ) is a mineral consisting of barium sulfate (BaSO4). Baryte is generally white or colorless, and is the main source of the element barium. The baryte group consists of baryte, celestine (strontium sulfate), anglesite (lead sulfate), and anhydrite (calcium sulfate). Baryte and celestine form a solid solution (Ba,Sr)SO4.

<span class="mw-page-title-main">Strontianite</span> Rare carbonate mineral and raw material for the extraction of strontium

Strontianite (SrCO3) 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.

<span class="mw-page-title-main">Aragonite</span> Calcium carbonate mineral

Aragonite is a carbonate mineral and one of the three most common naturally occurring crystal forms of calcium carbonate, the others being calcite and vaterite. It is formed by biological and physical processes, including precipitation from marine and freshwater environments.

<span class="mw-page-title-main">Stibnite</span> Sulfide mineral

Stibnite, sometimes called antimonite, is a sulfide mineral with the formula Sb2S3. This soft grey material crystallizes in an orthorhombic space group. It is the most important source for the metalloid antimony. The name is derived from the Greek στίβι stibi through the Latin stibium as the former name for the mineral and the element antimony.

<span class="mw-page-title-main">Galena</span> Natural mineral form of lead sulfide

Galena, also called lead glance, is the natural mineral form of lead(II) sulfide (PbS). It is the most important ore of lead and an important source of silver.

<span class="mw-page-title-main">Selenite (mineral)</span> Mineral variety of gypsum

Selenite, satin spar, desert rose, and gypsum flower are crystal habit varieties of the mineral gypsum.

<span class="mw-page-title-main">Anglesite</span> Lead sulfate mineral

Anglesite is a lead sulfate mineral with the chemical formula PbSO4. It occurs as an oxidation product of primary lead sulfide ore, galena. Anglesite occurs as prismatic orthorhombic crystals and earthy masses, and is isomorphous with barite and celestine. It contains 74% of lead by mass and therefore has a high specific gravity of 6.3. Anglesite's color is white or gray with pale yellow streaks. It may be dark gray if impure.

<span class="mw-page-title-main">Anhydrite</span> Mineral, anhydrous calcium sulfate

Anhydrite, or anhydrous calcium sulfate, is a mineral with the chemical formula CaSO4. It is in the orthorhombic crystal system, with three directions of perfect cleavage parallel to the three planes of symmetry. It is not isomorphous with the orthorhombic barium (baryte) and strontium (celestine) sulfates, as might be expected from the chemical formulas. Distinctly developed crystals are somewhat rare, the mineral usually presenting the form of cleavage masses. The Mohs hardness is 3.5, and the specific gravity is 2.9. The color is white, sometimes greyish, bluish, or purple. On the best developed of the three cleavages, the lustre is pearly; on other surfaces it is glassy. When exposed to water, anhydrite readily transforms to the more commonly occurring gypsum, (CaSO4·2H2O) by the absorption of water. This transformation is reversible, with gypsum or calcium sulfate hemihydrate forming anhydrite by heating to around 200 °C (400 °F) under normal atmospheric conditions. Anhydrite is commonly associated with calcite, halite, and sulfides such as galena, chalcopyrite, molybdenite, and pyrite in vein deposits.

<span class="mw-page-title-main">Alstonite</span>

Alstonite, also known as bromlite, is a low temperature hydrothermal mineral that is a rare double carbonate of calcium and barium with the formula BaCa(CO
3
)
2
, sometimes with some strontium. Barytocalcite and paralstonite have the same formula but different structures, so these three minerals are said to be trimorphous. Alstonite is triclinic but barytocalcite is monoclinic and paralstonite is trigonal. The species was named Bromlite by Thomas Thomson in 1837 after the Bromley-Hill mine, and alstonite by August Breithaupt of the Freiberg Mining Academy in 1841, after Alston, Cumbria, the base of operations of the mineral dealer from whom the first samples were obtained by Thomson in 1834. Both of these names have been in common use.

<span class="mw-page-title-main">Barytocalcite</span>

Barytocalcite is an anhydrous barium calcium carbonate mineral with the chemical formula BaCa(CO3)2. It is trimorphous with alstonite and paralstonite, that is to say the three minerals have the same formula but different structures. Baryte and quartz pseudomorphs after barytocalcite have been observed.

<span class="mw-page-title-main">Anglezarke</span> Human settlement in England

Anglezarke is a sparsely populated civil parish in the Borough of Chorley in Lancashire, England. It is an agricultural area used for sheep farming and is also the site of reservoirs that were built to supply water to Liverpool. The area has a large expanse of moorland with many public footpaths and bridleways. The area is popular with walkers and tourists; it lies in the West Pennine Moors in Lancashire, sandwiched between the moors of Withnell and Rivington, and is close to the towns of Chorley, Horwich and Darwen. At the 2001 census it had a population of 23, but at the 2011 census the population was included within Heapey civil parish. The area was subjected to depopulation after the reservoirs were built.

<span class="mw-page-title-main">Rampghill mine</span>

Rampgill mine is a disused lead mine at Nenthead, Alston Moor, Cumbria, England UK Grid Reference: NY78184351

<span class="mw-page-title-main">Serpierite</span>

Serpierite (Ca(Cu,Zn)4(SO4)2(OH)6·3H2O) is a rare, sky-blue coloured hydrated sulfate mineral, often found as a post-mining product. It is a member of the devilline group, which has members aldridgeite (Cd,Ca)(Cu,Zn)4(SO4)2(OH)6·3H2O, campigliaite Cu4Mn2+(SO4)2(OH)6·4H2O, devilline CaCu4(SO4)2(OH)6·3H2O, kobyashevite Cu5(SO4)2(OH)6·4H2O, lautenthalite PbCu4(SO4)2(OH)6·3H2O and an unnamed dimorph of devilline. It is the calcium analogue of aldridgeite and it is dimorphous with orthoserpierite CaCu4(SO4)2(OH)6·3H2O.

<span class="mw-page-title-main">Hokutolite</span>

Hokutolite is the only mineral named after a Taiwanese place among the more than 4,000 naturally occurring minerals in the world. Hokutolite is a rare mineral containing radioactive radium elements generated by the hot spring environment, and is currently found only in Beitou Hot Spring in Taipei City, and Tamagawa Hot Spring in Akita Prefecture, Japan. In Japan, the Ministry of Education, Culture, Sports, Science, and Technology has designated it as a "Special Natural Monument". In Taiwan, it is designated as a "Natural Cultural Landscape", and the Taipei City Government has designated a natural reserve in the Beitou River upstream of the Beitou Hot Spring Museum.

References

  1. Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi: 10.1180/mgm.2021.43 . S2CID   235729616.
  2. 1 2 3 4 5 Witherite mindat.org
  3. Handbook of Mineralogy
  4. 1 2 Webmineral data
  5. Mineralienatlas
  6. Ashburn, J.H., Mining Witherite in North-West Durham , Colliery Guardian, August 1963 (at Durham Mining Museum web-site)
  7. Withering, William (1784). "Experiments and Observations on Terra Poderosa" . Philosophical Transactions of the Royal Society of London. 74: 293–311. doi:10.1098/rstl.1784.0024. S2CID   186210361.
  8. ""William Withering (1741–1799): a biographical sketch of a Birmingham Lunatic." M R Lee, James Lind Library, accessed 25 September 2006" (PDF). Archived from the original (PDF) on 17 December 2008. Retrieved 9 February 2015.
  9. Starkey, R. E. (2011). "Matthew Boulton, his mineral collection and the Lunar Men". The Newsletter of the Russell Society. 59: 1–8.
  10. Watt, James Jr. (1789). Memoirs and Proceedings of the Manchester Philosophical Society. p. 598.
  11. 1 2 The Mining Magazine, March 1963, Vol 108, pages 133139
  12. 'Looking Back' p10 Hexham Courant 10 January 2014 featuring a photograph of Settlingstones miners in 1905
  13. 1 2 Wikisource-logo.svg One or more of the preceding sentences incorporates text from a publication now in the public domain :  Chisholm, Hugh, ed. (1911). "Witherite". Encyclopædia Britannica . Vol. 28 (11th ed.). Cambridge University Press. p. 759.
  14. Withering, William (1784). "Experiments and Observations on Terra Poderosa" . Philosophical Transactions of the Royal Society of London. 74: 293–311. doi:10.1098/rstl.1784.0024. S2CID   186210361.
  15. Whitelaw, G.P. (2003-10-25). "Standard Chrome Bath Control". finishing.com. Archived from the original on 13 December 2006. Retrieved 2006-11-29.

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