Minrecordite

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Minrecordite
Minrecordite and Dioptase - Tsumeb Mine, Namibia.jpg
Minrecordite (colorless) on dioptase from the Tsumeb Mine, Namibia
Clearly recognizable saddle-shaped crystal at the top right
General and classification
other names

IMA 1980-096

chemical formula CaZn [CO 3 ] 2
Mineral class
(and possibly department) 		Carbonates and nitrates
System no. to Strunz
and to Dana 		5.AB.10
02/14/01/04
Crystallographic Data
Crystal system trigonal
Crystal class ; symbol trigonal-rhombohedral; 3
Space group R 3 (No. 148)Template: room group / 148
Lattice parameters a  = 4.82  Å ; c  = 16.03 Å
Formula units Z  = 3
Physical Properties
Mohs hardness 3.5
Density (g / cm 3 ) measured: 3.45 (2); calculated: 3.445
Cleavage completely according to {10 1 4}
colour milk white to colorless
Line color White
transparency translucent
shine Glass gloss, pearlescent
Crystal optics
Refractive indices n ω  = 1.734 to 1.750
n ε  = 1.542 to 1.550
Birefringence δ = 0.192 to 0.200
Optical character uniaxial negative
Other properties
Chemical behavior Soluble in acids with release of CO 2

Minrecordite is a very seldom occurring mineral from the mineral class of "carbonates and nitrates" with the chemical composition CaZn [CO 3 ] 2 and therefore, chemically speaking, a calcium - zinc - carbonate .

Minrecordite crystallizes in the trigonal crystal system and develops translucent, colorless or white, rhombohedral crystals about 0.5 mm in size. These crystals often look like a mosaic or saddle , are often twinned and show a glass- like to mother-of-pearl-like sheen on the crystal surfaces .

Etymology and history

Minrecordite was first discovered in the Tsumeb Mine in Namibia and described in 1982 by Carlo G. Garavelli, Filippo Vurro, Gian Carlo Fioravanti. The mineral was named after the magazine The Mineralogical Record .

The type material of the mineral is stored in the Mineralogical Institute of the University of Bari in the Italian municipality of the same name under catalog no. HO-4/81 kept.

classification

Since the Minrecordite was only recognized as an independent mineral in 1980 and this was published in 1982, it is not listed in the outdated 8th edition of the mineral classification according to Strunz . Only in the "Lapis mineral directory", which was last updated in 2018, which, out of consideration for private collectors and institutional collections, is still based on this classic system of Karl Hugo Strunz , the mineral received the system and mineral number. V / B.03-40 . In the "lapis system" this corresponds to the class of "nitrates, carbonates and borates" and there corresponds to the section "anhydrous carbonates [CO 3 ] 2- , without foreign anions ", where minrecordite together with anchorite , benstonite , dolomite , huntite , Kutnohorite and norsethite form the "dolomite group".

The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and was updated by the International Mineralogical Association (IMA) until 2009, also assigns minrecordite to the category of “Carbonates without additional anions; without H 2 O “. This is, however, further subdivided according to the affiliation of the cations involved to certain element groups , so that the mineral can be found according to its composition in the subsection "alkaline earth (and other M 2+ ) carbonates", where it is only found together with anchorite, dolomite and Kutnohorit the "dolomite group" with the system no. 5.AB.10 forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns minrecordite to the class of "carbonates, nitrates and borates" and there in the department of "anhydrous carbonates". Here it is in the "Dolomite group (Trigonal: R 3 )" with the system no. 02/14/01 to be found in the subsection “ Anhydrous carbonates with the formula A + B 2+ (CO 3 ) 2 ”. Template: room group / 148

Crystal structure

Minrecordite crystallizes trigonal in the space group R 3 (space group no. 148) with the lattice parameters a  = 4.82  Å and c  = 16.03 Å as well as three formula units per unit cell . Template: room group / 148

Education and Locations

Minrecordite and dioptase from the Tsumeb Mine, Namibia (field of view 6 mm)

Minrecordit formed by hydrothermal processes in dolomitic dominated polymetallic ore - deposits . As Begleitminerale occur depending on the locality, among other calcite , Cerussite , Dioptas , zinc-containing dolomite, Duftit , malachite , Melnikovit , pyrite , quartz and sphalerite .

As a very rare mineral formation, Minrecordite has only become known in a few samples from less than 10 localities. Its type locality "Tsumeb Mine" is the only site in Namibia so far . Another possible location in the Talemzane meteorite crater in Algeria has not yet been confirmed.

In Europe, minrecordite has so far only been found in the Navan lead-zinc mine near the town of the same name in the Irish county of Meath and near Olkusz in Poland. The Mina da Preguiça near Sobral da Adiça in Portugal has not yet been confirmed as a possible further location.

On the American double continent, the mineral has so far been found in mineral samples from the M-5-00 well near Wellburns Creek in the Canadian province of Manitoba , near Annapolis in Iron County (Missouri) and in the Centennial Eureka Mine near Eureka ( Utah ) in the USA , in the Sierra Mojada in the municipality of the same name in the Mexican state of Coahuila and in a limestone mine with Cu-Zn-Pb-Ag mineralization near Cerro de Pasco in the Simón Bolívar district of the Pasco region of Peru .

The only known site in Asia so far is a polymetallic gold-silver mineralization near Penjom in the Raub district ( Pahang ) in Malaysia .

See also

literature

  • Carlo G. Garavelli, Filippo Vurro, Gian Carlo Fioravanti: Minrecordite, a new mineral from Tsumeb . In: The Mineralogical Record . tape 13 , no. 3 , May 1982, pp. 131-136 (English).
  • Michael Fleischer , Adolf Pabst : New Mineral Names . In: American Mineralogist . tape 68 , 1983, pp. 280–283 (English, available online at minsocam.org [PDF; 546 kB ; accessed on March 14, 2019]).

Web links

Commons : Minrecordite  - collection of pictures, videos and audio files

Individual evidence

  1. ↑ Malcolm Back, William D. Birch, Michel Blondieau and others: The New IMA List of Minerals - A Work in Progress - Updated: September 2019. (PDF 2672 kB) In: cnmnc.main.jp. IMA / CNMNC, Marco Pasero, September 2019, accessed October 3, 2019 .
  2. ↑ David Barthelmy: Minrecordite Mineral Data. In: webmineral.com. Retrieved March 14, 2019 .
  3. ^ 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.  287 (English).
  4. ↑ a b c d e f g h Minrecordite . 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; 65  kB ; accessed on March 14, 2019]).
  5. ↑ a b Stefan Weiß: The large Lapis mineral directory. All minerals from A - Z and their properties. Status 03/2018 . 7th, completely revised and supplemented edition. Weise, Munich 2018, ISBN 978-3-921656-83-9 .
  6. ↑ a b c Minrecordite. In: mindat.org. Hudson Institute of Mineralogy, accessed March 14, 2019 .
  7. ^ About the Mineralogical Record. In: mineralogicalrecord.com. The Mineralogical Record, accessed March 14, 2019 .
  8. ↑ Ernest H. Nickel, Monte C. Nichols: IMA / CNMNC List of Minerals 2009. (PDF 1703 kB) In: cnmnc.main.jp. IMA / CNMNC, January 2009, accessed October 3, 2019 .
  9. ↑ a b c List of locations where minrecordite was found in the Mineralienatlas and Mindat (accessed on October 3, 2019).