Minium

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Minium
Minium-232909.jpg
Minium from the Old Yuma Mine, Tucson Mountains , Arizona, USA ( overall size : 4.8 cm × 3.8 cm × 3.4 cm)
General and classification
chemical formula Pb 2+ 2 Pb 4+ O 4
Mineral class
(and possibly department) 		Oxides and hydroxides
System no. to Strunz
and to Dana 		4.BD.05 ( 8th edition : IV / B.06)
02/07/08/01
Crystallographic Data
Crystal system tetragonal
Crystal class ; symbol ditetragonal-dipyramidal; 4 / m  2 / m  2 / m
Space group P 4 2 / mbc (No. 135)Template: room group / 135
Lattice parameters a  = 8.811  Å ; c  = 6.563 Å
Formula units Z  = 4
Physical Properties
Mohs hardness 2.5
Density (g / cm 3 ) measured: 8.9 to 9.2 (synthetic); calculated: [8.92]
Cleavage completely along {110} and {010}
colour light red, brownish red, yellowish red
Line color yellow-orange
transparency translucent
shine weak greasy sheen, matt
Crystal optics
Refractive index n  = 2.42
Optical character uniaxial
Pleochroism Strong: X = deep reddish brown, Z = almost colorless

Minium , also known under the synonym red lead , is a rather seldom occurring mineral from the mineral class of " oxides and hydroxides ". It crystallizes in the tetragonal crystal system with the chemical composition Pb 2+ 2 Pb 4+ O 4 and is therefore chemically lead (II, IV) oxide .

Minium only develops microscopic crystals and is found in nature exclusively in the form of coarse or earthy masses and powdery hints of light red to brownish-red color with yellow-orange streak color .

Etymology and history

The mineral was already known to the Romans in ancient times, who gave it its name. So the term ' miniature painting ' also comes from Minium due to the frequent use of vermilion colors and not from ' small ' as it is often mistakenly assumed.

In German-speaking countries the name during the Middle Ages became redlead garbled . Minium was first systematically described in 1806 by James Smithson . He reported about it in a letter to Joseph Banks from Kassel , but did not give the exact location.

classification

Already in the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , the minium belonged to the mineral class of "oxides and hydroxides" and there to the department of "oxides with a molar ratio of metal: oxygen = 3: 4 (spinel type M 3 O 4 and related compounds) ”, where he formed the unnamed group IV / B.06 together with Apuanit , Kusachiit , Schafarzikit and Versiliait .

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 the minium in the department of "Oxides with the molar ratio of metal: oxygen = 3: 4 and comparable". However, this is further subdivided according to the relative size of the cations involved , so that the mineral can be found according to its composition in the subsection “With only large cations”, where it is the only member of the unnamed group 4.BD.05 .

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the minium to the class of "oxides and hydroxides" and there in the department of "multiple oxides". Here he is to be found as the only member of the unnamed group 07.02.08 within the subdivision "Multiple Oxides (A + B 2+ ) 2 X 4 , Spinel Group ".

Crystal structure

Minium crystallizes in tetragonal in the space group P 4 2 / mbc (space group no. 135) with the lattice parameters a  = 8.811  Å and c  = 6.563 Å as well as 4 formula units per unit cell . It should be noted that Minium is not a mixed oxide, but a lead (II) orthoplumbate . Template: room group / 135

Education and Locations

Handpiece with light red minium and solid lead in matrix from Cedar City (Utah) , USA (size: 6.5 cm × 5.0 cm × 4.0 cm)

Minium forms as a secondary mineral in some highly weathered (oxidised) lead - deposits . Often fires in the mines are likely to be responsible for the formation. It is associated with galena , Cerussite , Massikot , litharge , lead, Wulfenit and Mimetite .

As a rather rare mineral formation, minium can sometimes be abundant at various sites, but overall it is not very common. So far (as of 2015) around 260 sites are known.

In Germany, Minium appeared in several mines near Sehringen , Bleibach near Gutach im Breisgau , Gengenbach , Hausach and Aitern in the Black Forest in Baden-Württemberg; in a dolomite quarry near Altenmittlau , in the Alter Mann & Roter Küppel mine near Langhecke and the Mehlbach mine near Laubuseschbach in Hesse; in some pits in the Sankt Andreasberg and Clausthal-Zellerfeld mining areas in the Harz region of Lower Saxony ; in several mines in Niederbergisches Land and in Sauerland and Siegerland in North Rhine-Westphalia; in some pits and smaller sites in the Rhineland-Palatinate Eifel ; in the Giepenbach mine near Trautenstein in Saxony-Anhalt and the Holy Trinity mine near Zschopau in the Saxon Ore Mountains.

In Austria, the mineral has so far only been found in rock samples from the construction of the tunnel on Autobahn 10 near Kellerberg in Carinthia, on some slag heaps in the Kolm-Saigurn area in the Hüttwinkltal (valley head of the rear Rauris valley , Hohe Tauern) in Salzburg and on the Silberleithe in the Tyrolean community of Biberwier (Lechtal Alps).

In Switzerland, Minium is so far only known from the Ponte Aranno in the municipality of Novaggio in the canton of Ticino, from Les Trappistes in the municipality of Sembrancher and from the Crettaz mine on Mont Chemin near Martigny in the canton of Valais.

Other locations are in Australia, Belgium, Bolivia, Bulgaria, Chile, China, France, Gabon, Greece, Iran, Italy, Canada, Morocco, Mexico, Namibia, New Zealand, Norway, Russia, Sweden, Slovakia, Slovenia, Spain , South Africa, South Korea, Czech Republic, Turkmenistan, Hungary, the United Kingdom (England, Scotland, Wales) and the United States of America (Arizona, Colorado, Connecticut, Idaho, California, Missouri, Montana, Nevada, New Hampshire, New Mexico, New York, Utah, Virginia, Wisconsin).

At many of the sites, however, there are doubts about the natural origin of minium, since the mineral is also formed when lead ores are roasted, i.e. it is often formed as a by-product in slag from lead smelters.

use

Due to its intense color, minium has been used as a red pigment since ancient times (see also → lead (II, IV) oxide ). However, because of its toxicity, it is no longer used today. It is less common in European oil painting than the other red pigment, vermilion . Two well-known and convincing examples of the use of Minium are Albrecht Dürer's , "Jungfrau und Kind mit St Anna", 1519 and "La Coiffure" by Edgar Degas , around 1896.

See also

literature

  • James Smithson : Account of a discovery of native minium. In: Philosophical Transactions of the Royal Society of London. Volume 96, 1806, pp. 267–268 ( PDF 137.8 kB )

Web links

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

Individual evidence

  1. ↑ a b IMA / CNMNC List of Mineral Names; May 2015 (PDF 1.6 MB)
  2. ↑ JR Gavarri, G. Calvarin, D. Weigel: Oxydes de plomb. II. Etude structurale à 5 K de la phase orthorhombique de l'oxyde Pb 3 O 4 . In: Journal of Solid State Chemistry. Volume 14, 1975, pp. 91-98 doi: 10.1016 / S0022-4596 (74) 80044-7
  3. ↑ a b c Minium. In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America. 2001. ( PDF 59.7 kB )
  4. ↑ a b Mindat - Minium (English)
  5. ↑ Hans Lüschen: The names of the stones. The mineral kingdom in the mirror of language . 2nd Edition. Ott Verlag, Thun 1979, ISBN 3-7225-6265-1 , p. 273, 276 (minium = red lead) .
  6. ↑ James Smithson: Account of a discovery of native minium. In: Philosophical Transactions of the Royal Society of London. Volume 96, 1806, pp. 267-268. ( PDF 137.8 kB )
  7. ↑ Mindat - number of locations
  8. ↑ Find location list for Minium in the Mineralienatlas and in Mindat
  9. ^ Friedrich Klockmann : Klockmanns textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke , Stuttgart 1978, ISBN 3-432-82986-8 , pp.  508 (first edition: 1891).
  10. ^ Helmut Schrätze, Karl-Ludwig Weiner: Mineralogie. A textbook on a systematic basis . de Gruyter, Berlin / New York 1981, ISBN 3-11-006823-0 , p. 384 .
  11. ^ EW Fitzhugh: Red Lead and Minium, in Artists' Pigments. In: A Handbook of Their History and Characteristics. Volume 1, L. Feller, Ed., Cambridge University Press, London 1986, pp. 109-139.
  12. ↑ Red Lead at ColourLex