Ovamboit

Ovamboit
	Ovamboite crystal from the type locality Tsumeb, Namibia
General and classification
other names	IMA 1992-039
chemical formula	Cu 10 Fe 3 WGe 3 S 16 ; Cu 10 (Fe, Zn, Cu) 3 W (Ge, As) 3 S 16 ;
Mineral class; (and possibly department)	Sulfides and sulfosalts
System no. to Strunz ; and to Dana	2.CB.30 ; 02.09.04.04
Similar minerals	Maikainite , colusite
Crystallographic Data
Crystal system	cubic
Crystal class ; symbol	cubic-hexakistrahedral; 4 3 m
Space group	P 4 3 n (No. 218)
Lattice parameters	a = 10.68 Å
Formula units	Z = 1
Physical Properties
Mohs hardness	3.5 to 4 ; VHN 30 = 265-340; average 295
Density (g / cm 3 )	calculated: 4.736
Cleavage	is missing
Break ; Tenacity	not defined
colour	white, light yellow, pink to reddish gray in incident light
Line color	grey black
transparency	opaque
shine	Metallic luster
Crystal optics
Birefringence	no

Ovamboite is a very rarely occurring mineral from the mineral class of "sulfides and sulfosalts" with the idealized chemical composition Cu ₁₀ Fe ₃ WGe ₃ S ₁₆ and thus chemically a copper - iron - tungsten - germanium - sulfide . The iron and germanium contained in the formula are, however, often in natural Ovamboit by small amounts of zinc or a higher content of copper or by arsenic diadoch replaced , and therefore the formula in the form Cu ₁₀ (Fe, Zn, Cu) ₃ W (Ge, As) ₃ S ₁₆ can be written.

Ovamboite crystallizes in the cubic crystal system , but has so far only been found in the form of opaque, microcrystalline grains up to about 0.1 millimeter in diameter and crusty coatings. Under the incident light microscope , Ovamboit shows a whitish to light yellow or pink-gray color with a metallic sheen on the surfaces.

With maikainite, ovamboite forms a seamless series of mixed crystals , which is characterized by the substitution of tungsten by molybdenum .

Etymology and history

Ovamboite was first discovered in the " Tsumeb Mine" in the Oshikoto region of Namibia. It was first described in 2003 by Ernst M. Spiridonov. Since the name Tsumebit was already taken, Spiridonov named the new mineral after the historical region Ovamboland , in which the type locality Tsumeb is also located.

The type material of the mineral is stored in the Fersman Museum of the Russian Academy of Sciences in Moscow and in the Mining Museum in Saint Petersburg , Russia.

classification

In the 8th edition of the mineral classification according to Strunz , which has been obsolete since 1977 , the ovamboite is not yet listed. Only recently revised and updated Lapis mineral directory by Stefan Weiß, which is based on this classic system of Karl Hugo Strunz out of consideration for private collectors and institutional collections , the mineral received the system and mineral no. II / C.10-55 . In the "Lapis system" this corresponds to the class of "sulfides and sulfosalts" and there the section "sulfides with [the molar ratio ] metal: S, Se, Te ≈ 1: 1", where ovamboite together with colusite , germanite , germanocolusite , Maikainit , Morozeviczit , Nekrasovit , Polkovicit , Renierit , Stibiocolusit , Sulvanit and Vinciennit form an independent but unnamed group.

The 9th edition of Strunz's mineral systematics, which has been in force since 2001 and updated by the International Mineralogical Association (IMA) until 2009, also classifies ovamboite in the category of "Metal sulfides, M: S = 1: 1 (and similar)". However, this is further subdivided according to the predominant metals in the compound, so that the mineral can be found in the sub-section "with zinc (Zn), iron (Fe), copper (Cu), silver (Ag) etc." according to its composition , where together with colusite, germanite, germanocolusite, maikainite, nekrasovite and stibiocolusite the "germanite group" with the system no. 2.CB.30 forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns Ovamboite to the class of "sulfides and sulfosalts" and there to the department of "sulfide minerals". Here it is together with renierite, germanite and maikainite in the " germanite group " with the system no. 02.09.04 within the subsection "Sulphides - including selenides and tellurides - with the composition A _m B _n X _p , with (m + n): p = 1: 1".

Crystal structure

Ovamboite crystallizes cubically in the space group P 4 3 n (space group no. 218) with the lattice parameter a = 10.68 Å and one formula unit per unit cell . Template: room group / 218

Education and Locations

Ovamboite forms in metal-rich sulphide deposits . Baryte , bornite , galena , germanite , germanocolusite , maikainite , sphalerite and tennantite appear as accompanying minerals . Occasionally, ovamboite is fused with gallite in lamellar form .

The only known site Ovamboit is its type locality Tsumeb in Namibia.

literature

Ernst M. Spiridonov: Maikainite Cu ₂₀ (Fe, Cu) ₆ Mo ₂ Ge ₆ S ₃₂ and ovamboite Cu ₂₀ (Fe, Cu, Zn) ₆ W ₂ Ge ₆ S ₃₂ : new minerals in massive sulfide base metal ores . In: Doklady Earth Sciences . 393A, no. 3 , 2003, p. 1329–1332 (English, rruff.info [PDF; 258 kB ; accessed on June 1, 2019]).
John Leslie Jambor , Andrew C. Roberts: New mineral Names . In: American Mineralogist . tape 89 , 2004, p. 1826–1834 (English, minsocam.org [PDF; 464 kB ; accessed on June 1, 2019]).
Joseph A. Mandarino : New minerals . In: The Canadian Mineralogist . tape 42 , 2004, p. 1241–1260 (English, rruff.info [PDF; 250 kB ; accessed on June 1, 2019]).

Web links

Mineral Atlas: Ovamboite (Wiki)
Ovamboite. In: mindat.org. Hudson Institute of Mineralogy, accessed June 1, 2019 .
Ovamboite mineral data. (PDF 20 kB) In: www.mineralogicalassociation.ca. Mineralogical Association of Canada, May 15, 2015, accessed June 1, 2019 .

Individual evidence

↑ ^a ^b ^c Malcolm Back, William D. Birch, Michel Blondieau and others: The New IMA List of Minerals - A Work in Progress - Updated: March 2019. (PDF 1703 kB) In: cnmnc.main.jp. IMA / CNMNC, Marco Pasero, March 2019, accessed May 20, 2019 .
↑ ^a ^b ^c ^d ^e ^f ^g Stefan Weiss: The great 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 .
^ ^A ^b David Barthelmy: Ovamboite Mineral Data. In: webmineral.com. Accessed June 1, 2019 .
↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Ovamboite . 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; 131 kB ; accessed on June 1, 2019]).
↑ John L. Jambor, Andrew C. Roberts: New mineral Names . In: American Mineralogist . tape 89 , 2004, p. 1826–1834 (English, minsocam.org [PDF; 464 kB ; accessed on June 1, 2019]).
↑ Ernest H. Nickel, Monte C. Nichols: IMA / CNMNC List of Minerals 2009. (PDF 1703 kB) In: cnmnc.main.jp. IMA / CNMNC, January 2009, accessed April 25, 2019 .
↑ Find location list for Ovamboite at the Mineralienatlas and at Mindat

[IMA-Liste-2019-03-1] Malcolm Back, William D. Birch, Michel Blondieau and others: The New IMA List of Minerals - A Work in Progress - Updated: March 2019. (PDF 1703 kB) In: cnmnc.main.jp. IMA / CNMNC, Marco Pasero, March 2019, accessed May 20, 2019 .

[Lapis-2] ↑ ^a ^b ^c ^d ^e ^f ^g Stefan Weiss: The great 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 .

[Webmineral-3] A ^b David Barthelmy: Ovamboite Mineral Data. In: webmineral.com. Accessed June 1, 2019 .

[Datenblatt-4] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Ovamboite . 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; 131 kB ; accessed on June 1, 2019]).

[AM-89-2004-5] John L. Jambor, Andrew C. Roberts: New mineral Names . In: American Mineralogist . tape 89 , 2004, p. 1826–1834 (English, minsocam.org [PDF; 464 kB ; accessed on June 1, 2019]).

[IMA-Liste-2009-6] Ernest H. Nickel, Monte C. Nichols: IMA / CNMNC List of Minerals 2009. (PDF 1703 kB) In: cnmnc.main.jp. IMA / CNMNC, January 2009, accessed April 25, 2019 .

[Fundorte-7] Find location list for Ovamboite at the Mineralienatlas and at Mindat