Glushinskit

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Glushinskit
General and classification
chemical formula Mg (C 2 O 4 ) • 2H 2 O
Mineral class
(and possibly department) 		organic compounds / oxalates
System no. to Strunz
and to Dana 		10.AB.10 ( 8th edition : IX / A.01)
01.50.03.02
Similar minerals Whewellite , Weddellite
Crystallographic Data
Crystal system monoclinic
Crystal class ; symbol monoclinic prismatic; 2 / m
Space group C 2 / c (No. 15)Template: room group / 15
Lattice parameters a  = 12.67  Å ; b  = 5.41 Å; c  = 9.98 Å
β  = 129.4 °
Formula units Z  = 4
Physical Properties
Mohs hardness 2
Density (g / cm 3 ) 1.85
Cleavage Please complete!
colour colorless to white
Line color White
transparency translucent
shine Please complete!
Crystal optics
Refractive indices n α  = 1.365
n β  = 1.530
n γ  = 1.595
Birefringence δ = 0.230
Optical character biaxial negative
Other properties
Chemical behavior soluble in water

Glushinskit is a rare, secondary mineral from the mineral class of " organic compounds ". It crystallizes in the monoclinic crystal system with the composition Mg (C 2 O 4 ) · 2H 2 O, so it is chemically a magnesium oxalate .

Glushinskit is formed by the influence of plants on rocks containing magnesium. The crystals found so far were all microscopic (approx. 2.5 µm) and had a pyramidal habit . The mineral has a Mohs hardness of 2 and a white streak color.

Etymology and history

The mineral was named after the Russian geologist Pyotr Ivanovich Gluschinski (* 1908) who worked at the Institute for Arctic and Antarctic Research ( Saint Petersburg , Russia ) .

Glushinskit was first described in 1960 by Yuri Apollonivich Zhemchuzhnikov and AI Ginzburg.

Type material can be found in the Royal Museum , Edinburgh (Scotland) and the Natural History Museum , London (England).

classification

In the meanwhile outdated, but still in use 8th edition of the mineral classification according to Strunz , the Glushinskit belonged to the mineral class of "organic compounds" and there to the department of "salts of organic acids", where it together with Caoxit , Coskrenit- (Ce) , Humboldtin , Levinsonite (Y) , lindbergite , minguzzite , moolooite , natroxalate , novgorodovaite , oxammite , stepanovite , Weddellite , wheatleyite , whewellite , zhemchuzhnikovite and Zugshunstit- (Ce) formed the independent "group of oxalates ".

The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), also assigns the Glushinskit to the class of "organic compounds" and there to the department of "salts of organic acids". However, this section is further subdivided according to the type of salt-forming acid , so that the mineral can be found according to its composition in the sub-section "Oxalates", where it is the only representative of the Glushinskit group 10.AB.10 .

The systematics of minerals according to Dana also assigns the Glushinskit to the class of "organic minerals" and there in the department of the same name. Here it can be found with Humboldtin and Lindbergite in the Humboldtin group (50.01.03) within the subdivision " Salts of organic acids (oxalates) ".

Crystal structure

Glushinskit crystallizes monoclinically in the space group C 2 / c (space group no. 15) with the lattice parameters a  = 12.67  Å , b  = 5.41 Å, c  = 9.98 Å and β = 129.4 ° and 4 formula units per unit cell . Template: room group / 15

Glushinskit corresponds to a β-magnesium oxalate. It is known that magnesium oxalate also has an α-phase. This was found and described by Cogwill in 1989 as a natural mineral in the Chula Plain , Jordan Valley / Israel . There is no official name for this modification yet (as of 2011).

properties

Thermonalytical studies have shown that Glushinskit behaves completely analogously to pure magnesium oxalate . Like this, it gives off its water of crystallization at temperatures above 147 ° C and decomposes from 397 ° C to form magnesium oxide , carbon monoxide and carbon dioxide . Glushinskit is very soluble in water. For this reason it is not very stable as a mineral.

Education and Locations

Glushinskit was first found in northwest Scotland. Here the mineral was formed by the action of the lichen Lecanora atra on rock containing magnesium. Well-known sites in Scotland are:

In addition to the formation by lichen, Glushinskit was found in rotted parts of the saguaro cactus in Arizona .

Furthermore, the following sites have been described, although there is no information on education:

Even if these few localities suggest that Glushinskit is an extremely rare mineral, one can assume that it is often formed in nature. Larger crystals are not to be expected, however, since the formation is usually linked to plant influences and since magnesium oxalate, in contrast to calcium oxalates, has a high water solubility.

Furthermore, Glushinskit, like the analogous minerals Weddellite and Whewellite, was found in coal deposits. The formation takes place here as with the other oxalates. A well-known place of discovery are the coal deposits of

See also

literature

  • K. Kolo, Ph. Claeys: In vitro formation of Ca-oxalates and the mineral glushinskite by fungal interaction with carbonate substrates and seawater . In: Biogeosciences . tape 2 , 2005, p. 277–293 (English, biogeosciences.net [PDF; 7.7 MB ; accessed on January 23, 2019]).
  • Glushinskite . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America . 2001 (English, handbookofmineralogy.org [PDF; 66 kB ; accessed on January 23, 2019]).
  • PV Monje, EJ Baran: Evidence of formation of glushinskite as a biomineral in a Cactaceae species . In: Phytochemistry . tape 66 , no. 5 , 2005, p. 611-614 (English).

Web links

Individual evidence

  1. ^ A b c Hugo Strunz , Ernest H. Nickel : Strunz Mineralogical Tables. Chemical-structural Mineral Classification System . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p.  718 .
  2. ↑ a b MJ Wilson, D. Jones, JD Russel: Glushinskite, a naturally occurring magnesium oxalate . In: Mineralogical Magazine . tape 43 , 1980, pp. 837–840 (English, rruff.info [PDF; 325 kB ]).
  3. ↑ IAAR Official website of the Institute of Arctic and Antarctic Research (English / Russian); Reviewed on November 14, 2011.
  4. ^ YA Zhemchuzhnikov, AI Ginzburg: Petrology of clays . In: Izvestiya Akademii Nauk SSSR . 1960, p. 93 .
  5. ^ Ray L. Frost, Moses Adebajo, Matt L. Weier: A Raman spectroscopic study of thermally treated glushinskite - the natural magnesium oxalate dihydrate . In: Spectrochimica acta. Part A . 2004, p. 643–651 (English, edu.au [PDF; 568 kB ; accessed on January 23, 2019]).
  6. ↑ Laurence AJ Garvie: Decay-induced biomineralization of the saguaro cactuss (Carnegiea gigantea) . In: American Mineralogist . tape 88 , 2003, p. 1879–1888 (English, rruff.info [PDF; 936 kB ; accessed on January 23, 2019]).
  7. ^ Adelheid Fischer: Saguaro's end. In: researchmatters.asu.edu. Arizona State University - Knowledge Enterprise Development, March 26, 2007, archived from the original on March 9, 2016 ; accessed on January 23, 2019 .
  8. ↑ In vitro formation of Ca-oxalates and the mineral glushinskite by fungal interaction with carbonate substrates and seawater (accessed November 11, 2011; PDF; 15.5 MB)