Chalcophanite

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Chalcophanite
Chalcophanite - Mohawk Mine, Mohawk Hill, Clark Mountains, California, USA.jpg
Several nests of tabular chalcophanite from the Mohawk Mine, Clark Mountains, California, USA (image width: 4 mm)
General and classification
chemical formula (Zn, Fe 2+ , Mn 2+ ) Mn 3 4+ O 7 · 3H 2 O
Mineral class
(and possibly department) 		Oxides and hydroxides
System no. to Strunz
and to Dana 		4.FL.20 ( 8th edition : IV / F.11)
08/07/02/01
Crystallographic Data
Crystal system trigonal
Crystal class ; symbol trigonal-rhombohedral; 3
Room group (no.) R 3 (No. 148)
Lattice parameters a  = 7.57  Å ; c  = 20.82 Å
Formula units Z  = 6
Physical Properties
Mohs hardness 2.5
Density (g / cm 3 ) measured: 4.0; calculated: 3.872
Cleavage completely after {0001}
Break ; Tenacity thin crystals elastically pliable
colour bluish black
Line color brown
transparency opaque
shine Metallic luster

Chalcophanite is a rarely occurring mineral from the mineral class of " oxides and hydroxides ". It crystallizes in the trigonal crystal system with the chemical composition (Zn, Fe 2+ , Mn 2+ ) Mn 3 4+ O 7 · 3H 2 O and thus represents the zinc analogue of the manganese oxide aurorite . This is also optically very similar looking mineral can only be distinguished by a chemical analysis.

Chalcophanite usually develops kidney and stalactitic or granular to massive mineral aggregates , rarely also tabular crystals up to about 8 mm in size from violet to bluish-black color and metallic luster with brown streak color . The mineral is usually opaque, but in very thin layers it is translucent with deep red internal reflections.

Etymology and history

Chalcophanite was first discovered in 1875 in the “Passaic Mine” on Sterling Hill near Ogdensburg in Sussex County (New Jersey, USA) and described by Gideon Emmet Moore (1842–1895), who used the Greek words for the mineral due to its characteristic color change when ignited Χαλκός [Chalkos] for "copper" and φαίνο | μαι [fainomai] for "I show myself, I appear".

classification

In the meanwhile outdated, but still in use 8th edition of the mineral classification according to Strunz , the chalcophanite belonged to the mineral class of "oxides and hydroxides" and there to the department of "hydroxides and oxidic hydrates", where together with birnessite , aurorite, cianciulliite , ernienickelite and Jianshuiit formed a separate group.

The 9th edition of Strunz's mineral systematics , valid since 2001 and used by the International Mineralogical Association (IMA), also assigns chalcophanite to the class of oxides, more precisely to the “oxides (hydroxides, V [5,6]) vanadates, arsenides, antimonides , Bismuthide, Suldide, Selenide, Telluride, Jodide) "and there in the section" Hydroxide (without V or U) ". However, this section is further subdivided according to the presence of crystal water and / or hydroxyl groups as well as the type of link in the crystal structure, so that the mineral according to its composition and structure in the sub-section “Hydroxides with H 2 O ± (OH); Layers of edge-linked octahedra "can be found where it forms the unnamed group 4.FL.20 together with Aurorit, Ernienickelit and Jianshuiit .

The systematics of minerals according to Dana , which is common in the English-speaking world , assigns chalcophanite to the class of "oxides and hydroxides", but there in the department of "multiple oxides". Here he is the namesake of the "Chalcophanite group" with the system no. 08/07/02 with the other members Aurorit, Jianshuiit and Ernienickelit within the subdivision of " Multiple Oxides with Different Formulas ".

Crystal structure

Chalcophanite crystallizes trigonal in the space group R 3 (space group number 148) with the lattice parameters a  = 7.57  Å and c  = 20.82 Å as well as 6 formula units per unit cell .

Education and Locations

Some thick-tabular and prismatic chalcophanites from the Gold Hill Mine, Deep Creek Mountains, Utah
Nieriger chalcophanite from the "Cole Mine" near Bisbee in the Mule Mountains, Arizona

Chalcophanite is generally formed as a component in the weathering zone over zinc and manganese deposits . Accompanying minerals include birnessite , hetaerolite , kaolinite , cryptomelan , manganite , quartz , todorokite and woodruffite .

So far (as of 2010), chalcophanite has been found at around 140 sites around the world, including in Argentina , Australia , Bulgaria , Chile , Germany , France , Greece , Hungary , Italy , Japan , Kosovo , Mexico , Namibia , Norway , Austria , Russia , Spain , South Africa , Tunisia , the United Kingdom (Great Britain) and the United States of America (USA).

See also

Web links

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

Individual evidence

  1. ↑ Webmineral - Chalcophanite (English)
  2. ^ A b c 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.  244 .
  3. ↑ a b Chalcophanite , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 69.7 kB )
  4. ^ Helmut Schrätze, Karl-Ludwig Weiner: Mineralogie. A textbook on a systematic basis . de Gruyter, Berlin; New York 1981, ISBN 3-11-006823-0 , pp. 495 .
  5. ↑ Carl Hintze : Handbuch der Mineralogie , Walter de Gruyter & Co., Berlin, 1974 ISBN 3-11005850-2 , pp. 186-187 ( available online in the Google book search)
  6. ↑ Wagnerul.de (Mineralogical part Lavrion) - Aurorit
  7. ↑ Franklin and Sterling Hill, New Jersey: the world's most magnificent mineral deposits - Chalcophanite ( Memento from May 20, 2013 in the Internet Archive ) (descriptive paper by Gideon Moore, 1875)
  8. ↑ a b Mindat - Chalcophanite (English)