Lindgrenite

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Lindgrenite
Lindgrenite-107037.jpg
Lindgrenite from the "San Samuel" (also "San Manuel") pit, Carrera Pinto, Cachiyuyo de Llampos, Copiapó province , Atacama region , Chile
(field of view 4 mm)
General and classification
chemical formula Cu 3 [OH | MoO 4 ] 2
Mineral class
(and possibly department) 		Sulphates (selenates, tellurates, chromates, molybdates and tungstates)
System no. to Strunz
and to Dana 		7.GB.05 ( 8th edition : VI / G.02)
48.03.01.01
Crystallographic Data
Crystal system monoclinic
Crystal class ; symbol monoclinic prismatic; 2 / m
Room group (no.) P 2 1 / n (No. 14)
Lattice parameters a  = 5.39  Å ; b  = 14.02 Å; c  = 5.61 Å
β  = 98.5 °
Formula units Z  = 2
Frequent crystal faces {010}, {100}, {021}
Physical Properties
Mohs hardness 4.5
Density (g / cm 3 ) measured: 4.20; calculated: 4.29
Cleavage completely after {010}, indistinct after {101} and {100}
Break ; Tenacity not defined
colour green, yellowish green
Line color pale green
transparency transparent
shine weak glass luster, fat luster
Crystal optics
Refractive indices n α  = 1.930
n β  = 2.002
n γ  = 2.020
Birefringence δ = 0.090
Optical character biaxial negative
Axis angle 2V = 71 ° (measured); 50 ° (calculated)
Other properties
Chemical behavior soluble in hydrochloric acid and nitric acid

Lindgrenite is a rarely occurring mineral from the mineral class of " sulfates (and relatives, see classification )". It crystallizes in the monoclinic crystal system with the chemical composition Cu 3 [OH | MoO 4 ] 2 , and is thus chemically seen a copper - molybdate with additional hydroxide .

Lindgrenite is transparent and develops only small crystals up to about two centimeters in size with a needle-like to tabular habit , which can be streaked along the c-axis. It is mostly found in the form of coarse (massive) aggregates and crusty coatings. Its color varies between green and yellowish green, depending on the thickness of the crystals, but its line color is only pale green. Unweathered crystal surfaces have a weak, glass-like or fat-like sheen .

Special properties

Lindgrenite is soluble in hydrochloric acid and nitric acid .

Etymology and history

Lindgrenite was first discovered in the Chuquicamata opencast copper mine in the Chilean Región de Antofagasta and described in 1935 by Charles Palache , who named the mineral after the Swedish-American geologist Waldemar Lindgren .

classification

In the meanwhile outdated, but still in use 8th edition of the mineral classification according to Strunz , the Lindgrenite belonged to the mineral class of " sulfates , chromates , molybdates and tungstates (as well as some selenates and tellurates)" and there to the department of "molybdates and tungstates", where he together with ferric molybdite the "Lindgrenite ferric molybdite group" with the system no. VI / G.02 and the other members Biehlit , Cuprotungstit , Szenicsit and Vergasovait .

The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), assigns Lindgrenite to the class of "sulfates (selenates, tellurates, chromates, molybdates and wolframates)" and also to the department of "Molybdates and Wolframates". However, this is further subdivided according to the possible presence of additional anions and / or water of crystallization , so that the mineral can be found according to its composition in the subsection “With additional anions and / or H 2 O”, where it is the only member of the unnamed group 7 .GB.05 forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns Lindgrenite to the class of "phosphates, arsenates and vanadates", but also to the category of "molybdates and tungstates". Here he is the only member of the unnamed group 48.03.01 within the sub-section " Anhydrous molybdates and tungstates (basic and anhydrous) ".

Education and Locations

Crusty coating of lindgrenite crystals from the "Inspiration Mine", Miami-Inspiration district, Gila County , Arizona, USA (size: 2 cm)

Lindgrenite forms secondarily in the oxidation zone of molybdenum-containing copper deposits . As accompanying minerals may include Antlerit , Brochantite , chrysocolla various iron oxides , molybdenite , Powellit and quartz occur.

As a rare mineral formation, Lindgrenite could only be detected at a few sites, with around 20 sites being known to date (as of 2013). Besides its type locality , the open pit copper mine Chuquicamata, the mineral occurred in Chile in the pit " Santa Catalina " in the Antofagasta Region , into several pits Atacama and in the pit "Braden" (also called "Teniente") near Rancagua in the Región del Libertador General Bernardo O'Higgins on.

In addition, Lindgrenit was also found in the " Vaulry " mine in the French canton of Nantiat (Limousin), in the "Sansei" mine in the Japanese prefecture of Nara (Honshū), in the copper mine "Klauvreidnuten" ( Kløvreidnuten ) near Klauvreid in the Norwegian province of Telemark and found in several locations in the US states of Arizona , California, and Idaho .

Crystal structure

Lindgrenite crystallizes monoclinically in the space group P 2 1 / n (space group no. 14) with the lattice parameters a  = 5.39  Å ; b  = 14.02 Å; c  = 5.61 Å and; β = 98.5 ° and 2 formula units per unit cell .

See also

literature

Web links

Commons : Lindgrenite  - collection of images, videos and audio files

Individual evidence

  1. ↑ a b c d e Hugo Strunz , Ernest H. Nickel: Strunz Mineralogical Tables . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p.  420 .
  2. ↑ Webmineral - Lindgrenite
  3. ↑ a b c Lindgrenite. In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America. 2001. ( PDF 67 kB )
  4. ↑ a b c Mindat - Lindgrenite
  5. ↑ Mindat - Number of localities for Lindgrenit
  6. ↑ Find location list for Lindgrenite at the Mineralienatlas and at Mindat