Manganite
| Manganite | |
|---|---|
 |
|
| General and classification | |
| other names |
|
| chemical formula | γ-MnO (OH) |
|
Mineral class (and possibly department) |
Oxides and hydroxides |
|
System no. to Strunz and to Dana |
4.FD.15 ( 8th edition : IV / F.06) 01/06/03/01 |
| Similar minerals | Enargite , stibnite , zinkenite |
| Crystallographic Data | |
| Crystal system | monoclinic |
| Crystal class ; symbol | monoclinic prismatic; 2 / m |
| Room group (no.) | P 2 1 / c (No. 14) (No. 14) |
| Lattice parameters |
a = 5.304 (1) Å ; b = 5.277 (1) Å; c = 5.304 (1) Å β = 114.38 (2) ° |
| Formula units | Z = 4 |
| Frequent crystal faces | {001}, {h0l} |
| Twinning | Contact and penetration twins according to {011}, lamellar according to {100} |
| Physical Properties | |
| Mohs hardness | 4th |
| Density (g / cm 3 ) | measured: 4.29 to 4.34; calculated: 4.38 |
| Cleavage | perfect after {110}, good after {001} |
| Break ; Tenacity | uneven to scalloped |
| colour | black to black-gray |
| Line color | red-brown to black |
| transparency | opaque |
| shine | Metal gloss, matt |
| Crystal optics | |
| Refractive indices |
n α = 2.250 (2) n β = 2.250 (2) n γ = 2.530 (2) |
| Birefringence | δ = 0.280 |
| Optical character | biaxial positive |
Manganite , as Braunmanganerz , Glanzmanganerz or short Braunstein known (not to be confused with the mineral group of brown stones ), is a common mineral from the mineral class of " oxides and hydroxides ". It crystallizes in the monoclinic crystal system with the chemical composition γ-MnO (OH), so it consists in equal parts of manganese in the face-centered cubic modification , oxygen and hydroxide ions (OH).
Manganite mostly develops prismatic crystals striped along the c-axis and knee-shaped or cross-shaped crystal twins , but also needle-like and granular to massive mineral aggregates or concretions . Also pseudomorphs after calcite are known.
Manganite is usually opaque and gray-black to black in color with red-brown to black streak color . In the thinnest layers and splinters, however, it can be reddish translucent. Visible crystal surfaces show a strong, occasionally colorful, iridescent metal luster , broken surfaces and massive aggregates, on the other hand, are matt.
Etymology and history
Manganite was first discovered in Ilfeld in the Nordhausen district (Thuringia) in the southern Harz region and described in 1827 by Wilhelm Ritter von Haidinger , who named the mineral based on its manganese content.
classification
In the now outdated, but still in use 8th edition of the mineral classification according to Strunz , manganite belonged to the mineral class of "oxides and hydroxides" and there to the department of "hydroxides and oxidic hydrates (water-containing oxides with a layered structure)", where together with Akaganeit , Boehmite , Diaspor , Feitknechtit , Feroxyhyt , Goethite , Groutit , Lepidokrokit , Schwertmannite and Tsumgallit the "Akaganeit-Group" with the system no. IV / F.06 .
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 assigns manganite to the class of "oxides and hydroxides", but in the new section of "hydroxides (without V or U )" a. This section is further subdivided according to the possible presence of OH groups and crystal water as well as the crystal structure, so that the mineral according to its composition and structure is classified in the sub-section “Hydroxides with OH, without H 2 O; Chains from edge-sharing octahedra ”can be found, where it is the only member of the unnamed group 4.FD.15 .
The systematics of minerals according to Dana also assigns manganite to the class of "oxides and hydroxides" and there into the department of "hydroxides and hydroxides containing oxides". Here he is to be found as the only member of the unnamed group 01/06/03 within the subdivision of " Hydroxides and hydroxy-containing oxides with the formula: X 3+ O OH ".
Crystal structure
Manganite crystallizes monoclinically in the space group P 2 1 / c (space group no. 14) with the lattice parameters a = 5.304 (1) Å ; b = 5.277 (1) Å; c = 5.304 (1) Å and β = 114.38 (2) ° and 4 formula units per unit cell .
properties
The water of crystallization contained in the manganite only escapes at over 200 ° C. The mineral dissolves in concentrated hydrochloric acid , whereby chlorine separates. The manganese reaction can be seen in the borax bead in front of the soldering tube .
Over time, manganite changes into pyrolusite due to weathering , whereby the already often existing stripes become more and more holey.
Modifications and varieties
The compound γ-MnO (OH) is trimorphic and occurs in nature in addition to monoclinic manganite as trigonal crystallizing feitknechtite and orthorhombic crystallizing groutite .
Education and Locations
Manganite is formed by hydrothermal deposition at relatively low temperature (200-100 ° C), but also secondary in manganese-containing ore - transitions . It is also rarely formed by sedimentary deposits or metamorphic transformation in manganese-rich rocks. Accompanying minerals include Braunite , barite , calcite , goethite , hausmannite , pyrolusite and siderite .
So far (as of 2011) manganite has been detected at around 650 sites worldwide. Above all, its type locality Ilfeld and other sites in the Harz are known from Druze finds with crystals up to 4 cm in size. In addition, the mineral could still be found in Thuringia near Kamsdorf and Langewiesen and in several places in the Black Forest in Baden-Württemberg; near Lichtenberg and Hartkoppe ( Sailauf ) in Bavaria, in the district of Gießen , near Steeden , Ober-Rosbach and Wetzlar in Hesse; Peine in Lower Saxony; Sauerland and Siegerland in North Rhine-Westphalia; in several regions of Rhineland-Palatinate ; at Wadern in Saarland; Mansfeld in Saxony-Anhalt and at Schneeberg in Saxony.
In Austria, manganite occurred mainly in several regions of Carinthia , Styria and Upper Austria as well as near Baunzen in the Lower Austrian municipality of Purkersdorf . In Switzerland, the mineral was found in the communities of Tinizong-Rona and Ausserferrera in the canton of Graubünden, in Thayngen in Schaffhausen and in Turtmann in Valais.
Other locations are Egypt , Argentina , Australia , Belgium , Brazil , Bulgaria , Chile , China , Finland , France , Gabon , Georgia , Ghana , Greece , India , Iran , Ireland , Italy , Japan , Canada , Cuba , Madagascar , Morocco , Mexico , Namibia , New Caledonia , New Zealand , Norway , Pakistan , Poland , Portugal , Rwanda , Romania , Russia , Sweden , Slovakia , Spain , South Africa , South Korea , Czech Republic , Turkey , Ukraine , Hungary , Uzbekistan , the United Kingdom (Great Britain) and the United United States of America (USA).
use
Manganite is an important manganese ore with a manganese content of up to 62.5%.
See also
literature
- W. Haidinger: On the crystalline forms and properties of the manganese ores . In: The Edinburgh Journal of Science . tape 4 , 1826, pp. 41–50 ( rruff.info [PDF; 799 kB ; accessed on September 1, 2017]).
- Thomas Kohler, Thomas Armbruster, Eugen Libowitzky: Hydrogen bonding and Jahn-Teller distortion in groutite, α-MnOOH, and manganite, γ-MnOOH, and their relations to the manganese dioxides ramsdellite and pyrolusite . In: Journal of Solid State Chemistry . tape 133 , 1997, pp. 486–500 ( unibe.ch [PDF; 596 kB ; accessed on September 1, 2017]).
- Manganites . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America . 2001 ( handbookofmineralogy.org [PDF; 71 kB ; accessed on September 1, 2017]).
- Petr Korbel, Milan Novák: Mineral Encyclopedia (= Villager Nature ). Nebel Verlag, Eggolsheim 2002, ISBN 978-3-89555-076-8 , p. 110 .
Web links
- Mineral Atlas: Manganite (Wiki)
- RRUFF Database-of-Raman-spectroscopy - Manganite (English)
Individual evidence
- ^ A b 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. 236 .
- ↑ Webmineral - Manganite (English)
- ↑ a b c Thomas Kohler, Thomas Armbruster, Eugen Libowitzky: Hydrogen bonding and Jahn-Teller distortion in groutite, α-MnOOH, and manganite, γ-MnOOH, and their relations to the manganese dioxides ramsdellite and pyrolusite . In: Journal of Solid State Chemistry . tape 133 , 1997, pp. 486–500 ( unibe.ch [PDF; 596 kB ; accessed on September 1, 2017]).
- ↑ a b c d Mindat - Manganite (English)
- ↑ a b c Friedrich Klockmann : Klockmanns textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke, Stuttgart 1978, ISBN 3-432-82986-8 , pp. 555–556 (first edition: 1891).
- ↑ Find location list for manganite in the Mineralienatlas and Mindat