Widgiemoolthalite: Difference between revisions
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==Structure== |
==Structure== |
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Widgiemoolthalite is a [[nickel(II) carbonate]] that has undergone [[mineral hydration]]. Tests by Nickel, Robinson, and Mumme yielded the chemical formula {{nowrap|(Ni,Mg)<sub>5.00</sub>(CO<sub>3</sub>)<sub>4.15</sub>-(OH)<sub>1.70</sub>•5.12H<sub>2</sub>O.}} The researchers observed that widgiemoolthalite is the nickel [[structural analog#Chemistry|structural analog]] to the hydrated magnesium [[carbonate mineral|carbonate]] [[hydromagnesite]] and considering this relationship, determined that widgiemoolthalite's ideal makeup to be {{nowrap|Ni<sub>5</sub>(CO<sub>3</sub>)<sub>4</sub>(OH)<sub>2</sub>•4-5H<sub>2</sub>O.}}<ref name="discovery" /> |
Widgiemoolthalite is a [[nickel(II) carbonate]] that has undergone [[mineral hydration]]. Tests by Nickel, Robinson, and Mumme yielded the chemical formula {{nowrap|(Ni,Mg)<sub>5.00</sub>(CO<sub>3</sub>)<sub>4.15</sub>-(OH)<sub>1.70</sub>•5.12H<sub>2</sub>O.}} The researchers observed that widgiemoolthalite is the nickel [[structural analog#Chemistry|structural analog]] to the hydrated magnesium [[carbonate mineral|carbonate]] [[hydromagnesite]] and considering this relationship, determined that widgiemoolthalite's ideal makeup to be {{nowrap|Ni<sub>5</sub>(CO<sub>3</sub>)<sub>4</sub>(OH)<sub>2</sub>•4-5H<sub>2</sub>O.}}<ref name="discovery" /> |
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Crystals of widgiemoolthalite conform to a [[Monoclinic crystal system|monoclinic]] system of [[Crystal structure#Classification|symmetry]].<ref name="thermo" /> |
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==Characteristics== |
==Characteristics== |
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Revision as of 20:43, 15 May 2016
Widgiemoolthalite
Origins
Widgiemoolthalite was first found at 132 North, a nickel mine near Widgiemooltha, Western Australia. Blair J. Gartrell collected the holotype widgiemoolthalite specimen from a stockpile of secondary minerals at the site. The mineral was discovered in 1992 and was first reported in the American Mineralogist in 1993 by Ernest H. Nickel, Bruce W. Robinson, and William G. Mumme, when it received its name for its type locality.[1][2] Widgiemoolthalite's existence and name were approved by the Commission on New Minerals and Mineral Names of the International Mineralogical Association the same year. The holotype specimen was stored in Perth's Western Australian Museum.[1]
Occurrence
Widgiemoolthalite occurs as a secondary mineral. It is found overlaying nickel sulfide that has undergone weathering, often in hollow spaces on gaspeite surfaces.[1] Other minerals associated with widgiemoolthalite include annabergite, carrboydite, dolomite, glaukosphaerite, hydrohonessite, kambaldaite, magnesite, nepouite, nullaginite, olivenite, otwayite, paratacamite, pecoraite, reevesite, retgersite, and takovite.[1][3] Two additional unnamed minerals were also reported as associated secondary minerals from the 132 North site, the only locality at which widgiemoolthalite has been found.[3][4]
Structure
Widgiemoolthalite is a nickel(II) carbonate that has undergone mineral hydration. Tests by Nickel, Robinson, and Mumme yielded the chemical formula (Ni,Mg)5.00(CO3)4.15-(OH)1.70•5.12H2O. The researchers observed that widgiemoolthalite is the nickel structural analog to the hydrated magnesium carbonate hydromagnesite and considering this relationship, determined that widgiemoolthalite's ideal makeup to be Ni5(CO3)4(OH)2•4-5H2O.[1]
Crystals of widgiemoolthalite conform to a monoclinic system of symmetry.[2]
Characteristics
Hand specimens of widgiemoolthalite tend to be bluish-green though may also be grass-green in rare cases, while the mineral's streak is pale bluish-green. Widgiemoolthalite is transparent in hand sample with a silky luster. The mineral is brittle and breaks along its fiber contacts. Its observed specific gravity is 3.13 while its calculated specific gravity is 3.24, with a hardness of 3.5 on the Mohs scale.[1][4]
When viewed with polarized light under a petrographic microscope, widgiemoolthalite appears bluish-green and does not exhibit pleochroism. It is biaxial positive and has a high optic angle (or 2V).[1]
References
- ^ a b c d e f g Nickel, E. H.; Robinson, B. W.; Mumme, W. G. (1993). "Widgiemoolthalite: The new Ni analogue of hydromagnesite from Western Australia" (PDF). American Mineralogist. 78: 819–821.
- ^ a b Gamsjäger, H.; Bugajski, J.; Gajda, T.; Lemire, R. J.; Preis, W. (2005). Chemical Thermodynamics of Nickel. Amsterdam: Elsevier. p. 216. ISBN 0-444-51802-9.
- ^ a b Nickel, E. H.; Clout, J. F. M.; Gartrell, B. J. (July 1994). "Secondary nickel minerals from Widgiemooltha". Mineralogical Record. 25 (4): 283–291 – via ProQuest.
{{cite journal}}: Unknown parameter|subscription=ignored (|url-access=suggested) (help) - ^ a b "Widgiemoolthalite". Mindat.org. Hudson Institute of Mineralogy. May 1, 2016. Retrieved May 3, 2016.