Zincite

Zincite
	Zincite, crystal specimen from Arizona
General and classification
chemical formula	ZnO
Mineral class; (and possibly department)	Oxides and hydroxides
System no. to Strunz ; and to Dana	4.AB.20 ( 8th edition : IV / A.03) ; 02/04/02/01
Crystallographic Data
Crystal system	hexagonal
Crystal class ; symbol	dihexagonal-pyramidal; 6 mm
Space group	P 6 3 mc (No. 186)
Lattice parameters	a = 3.249 Å ; c = 5.207 Å
Formula units	Z = 2
Physical Properties
Mohs hardness	4th
Density (g / cm 3 )	5.64 to 5.68
Cleavage	completely according to {10 1 0}
Break ; Tenacity	shell-like
colour	white, yellow, orange, red
Line color	orange yellow
transparency	transparent to translucent
shine	strong fat luster, diamond luster
Crystal optics
Refractive indices	n ω = 2.013 ; n ε = 2.029
Birefringence	δ = 0.016
Optical character	uniaxial positive
Pleochroism	ω = yellow; ε = dark red
Other properties
Chemical behavior	sensitive to various acids

Zincite , also known under the outdated, mining term red zinc ore , is a rarely occurring mineral from the mineral class of oxides (and hydroxides) with the chemical formula ZnO. It consists of zinc and oxygen in a ratio of 1: 1 and is therefore chemically zinc oxide . Naturally occurring zincite always contains small amounts of manganese (up to 9%) and / or iron , so that its formula is also given as (Zn, Mn) O or (Zn, Mn ²⁺ , Fe ²⁺ ) O, depending on the source becomes.

Zincite crystallizes in the hexagonal crystal system and usually develops granular to massive aggregates , but rarely also forms pyramidal crystals up to about 2.5 cm in size, which are yellow to orange-red in color and have a fat to diamond-like shine on the surfaces .

Etymology and history

Zinkit was first described in 1845 by Wilhelm Ritter von Haidinger . The mineral got its name because of its high zinc content of over 73%.

classification

Already in the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , zincite belonged to the mineral class of "oxides and hydroxides" and there to the department of "oxides with a metal: oxygen ratio = 1: 1 and 2: 1 (M ₂ O, MO) ", where together with bromellite he created the" bromellite series "with the system no. IV / A.03 .

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 classifies zincite in the category of “Oxides with a metal: oxygen ratio of 2: 1 and 1: 1”. However, this is further subdivided according to the exact molar ratio and the relative size of the cations involved , so that the mineral is classified according to its composition in the subsection “Cation: Anion (M: O) = 1: 1 (and up to 1: 1.25); with only small to medium-sized cations ”, where the newly named“ zincite group ”with the system no. 4.AB.20 forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the to the class of "oxides and hydroxides" and there in the department of "oxides". Here, too, it can be found together with bromellite in the 04.02.02 group, which was not named this time, within the sub-section “ Simple oxides with a cation charge of 2+ (AO) ”.

Crystal structure

Zincite crystallizes isotypically with wurtzite in the hexagonal crystal system in the space group P 6 ₃mc (space group no. 186) with the lattice parameters a = 3.249 Å and c = 5.207 Å as well as two formula units per unit cell . Template: room group / 186

properties

morphology

Synthetic zincite crystals

In nature, zincite only rarely develops well-formed crystals with preferably growing crystal faces (40 4 5), (10 1 3) and (10 1 1). The crystal bodies are hemimorphic, that is, they show a different area development at the two ends of the c axis.

Synthetic crystals, which sometimes occur as a by-product and furnace breakage during zinc production, on the other hand, preferentially develop the areas (10 1 0), (0001), (000 1 ), (10 1 1) and (10 1 3). In addition, in contrast to their natural counterparts, they are usually colorless or greenish-yellow to honey-brown.

Chemical properties

Zincite is soluble in hydrochloric , sulfuric and nitric acid, but not in hydrofluoric acid , as the poorly soluble zinc fluoride is formed there.

Education and Locations

Zincite is produced by the so-called contact metamorphosis, that is, by a series of chemical-physical processes that occur when hot igneous melts rise and cause a transformation of the surrounding rocks through the action of heat. The rocks that are formed during this process depend on the composition of the magma and on the type of rocks involved.

So far Zincite was on the following localities minded : Western Australia in Australia; Liège (Plombières), Limburg (Dilsen-Stokkem) and Namur (Andenne) in Belgium; Haskovo Oblast in Bulgaria; Hesse (Richelsdorf), Lower Saxony (Goslar district), North Rhine-Westphalia (Aachen, Sauerland), Rhineland-Palatinate (Lahntal, Siegerland) and Saxony (Ore Mountains) in Germany; Attica in Greece; East Azerbaijan in Iran; Liguria , Lombardy , Sardinia and Tuscany in Italy; Viken in Norway; Katanga in the Congo ; Gmünd in Carinthia , Annaberg (Lower Austria) and Öblarn / Styria in Austria; Eastern Siberia in Russia; Dalarna in Sweden; Košice in Slovakia; Bohemia in the Czech Republic; as well as Arizona , California , Colorado , Nevada , New Jersey , New Mexico , Utah, and Virginia .

use

faceted zincite from Poland, 5.26ct

In local accumulation, zincite serves as zinc ore. The zinc and manganese mines of Sterling Hill in Ogdensburg and Mine Hill in Franklin, New Jersey, are particularly known for their abundant zincite deposits . Zincites of good quality are seldom cut as gem stones , mainly for sale to collectors.

literature

Paul Ramdohr , Hugo Strunz : Klockmann's textbook of mineralogy . 16th edition. Ferdinand Enke Verlag, 1978, ISBN 3-432-82986-8 , pp. 499 .
Walter Schumann: Precious stones and gemstones . 13th edition. BLV Verlag, 1976, ISBN 3-405-11381-4 , p. 222 .

Web links

Commons : Zinkit (Zincite) - collection of images, videos, and audio files

Mineral Atlas: Zincite (Wiki)
Zincite. In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America. 2001 ( PDF 66.7 kB )

Individual evidence

↑ ^a ^b ^c ^d Webmineral - Zincite (engl.)
↑ ^a ^b ^c American Mineralogist Crystal Structure Database - Zincite (Engl., 1993)
↑ ^a ^b ^c ^d Zincite at mindat.org (engl.)
↑ Stefan Weiß: The large Lapis mineral directory . 5th edition. Christian Weise Verlag, Munich 2008, ISBN 978-3-921656-70-9 .
↑ Zincite. In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America. 2001 ( PDF 66.7 kB )
^ Walter Schumann: Collecting stones and minerals; find, prepare, determine . BLV Buchverlag, Munich / Vienna / Zurich 1994, ISBN 3-405-14590-2 , p. 110 .
↑ Find location list for zincite in the Mineralienatlas and Mindat

[Webmineral-1] Webmineral - Zincite (engl.)

[AMCSD-2] American Mineralogist Crystal Structure Database - Zincite (Engl., 1993)

[Mindat-3] Zincite at mindat.org (engl.)

[Lapis-4] Stefan Weiß: The large Lapis mineral directory . 5th edition. Christian Weise Verlag, Munich 2008, ISBN 978-3-921656-70-9 .

[Datenblatt-5] Zincite. In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America. 2001 ( PDF 66.7 kB )

[Schumann-6] Walter Schumann: Collecting stones and minerals; find, prepare, determine . BLV Buchverlag, Munich / Vienna / Zurich 1994, ISBN 3-405-14590-2 , p. 110 .

[Fundorte-7] Find location list for zincite in the Mineralienatlas and Mindat