Mallardite
| Mallardite | |
|---|---|
| General and classification | |
| other names |
Manganese Vitriol |
| chemical formula | Mn [SO 4 ] • 7H 2 O |
|
Mineral class (and possibly department) |
Sulphates (selenates, tellurates, chromates, molybdates and tungstates) |
|
System no. to Strunz and to Dana |
7.CB.35 ( 8th edition : VI / C.06) 06/29/10/05 |
| Crystallographic Data | |
| Crystal system | monoclinic |
| Crystal class ; symbol | monoclinic prismatic; 2 / m |
| Space group | P 2 1 / c (No. 14) |
| Lattice parameters |
a = 14.15 Å ; b = 6.50 Å; c = 11.06 Å β = 105.6 ° |
| Formula units | Z = 4 |
| Physical Properties | |
| Mohs hardness | ≈ 2 |
| Density (g / cm 3 ) | measured: 1.846 (synthetic); calculated: 1.838 |
| Cleavage | good after {001}, possibly also after {110} |
| colour | colorless, white to light pink |
| Line color | White |
| transparency | transparent to translucent |
| shine | Glass gloss |
| Crystal optics | |
| Refractive indices |
n α = 1.462 n β = 1.465 n γ = 1.474 |
| Birefringence | δ = 0.012 |
| Optical character | biaxial positive |
| Other properties | |
| Chemical behavior | water soluble, dehydrated at room temperature |
Mallardite is a very rare mineral from the mineral class of "sulfates (and relatives, see classification )" with the chemical composition Mn [SO 4 ] · 7H 2 O and is therefore chemically a water-containing manganese (II) sulfate , more precisely Heptahydrate.
Mallardite crystallizes in the monoclinic crystal system , but so far no well-formed crystals that are visible to the naked eye have been discovered. Usually the mineral occurs in the form of fibrous masses of up to 12 cm in size and as efflorescence or crusty coatings on other minerals. Synthetically produced mallardite crystals, however, are tabular.
In its pure form, mallardite is colorless and transparent. However, due to multiple refraction due to lattice construction defects or polycrystalline formation, it can also appear white and, due to foreign admixtures, take on a light pink color, with the transparency decreasing accordingly.
Etymology and history
Was first discovered in the Mallardit Silbererzgrube Lucky Boy Mine in Butterfield Canyon on the Great Salt Lake (Great Salt Lake) in the same County of the US state of Utah. It was first described in 1879 by Marie Adolphe Carnot , who named the mineral after the French crystallographer and mineralogist François Ernest Mallard .
The type material is available in the Muséum national d'histoire naturelle in Paris under catalog no. 96132 kept.
classification
In the outdated, but partly still in use, 8th edition of the mineral classification according to Strunz , the mallardite belonged to the mineral class of "sulfates, chromates, molybdates, tungstates (including selenates and tellurates)" and there to the department "C. Sulphates containing water, without foreign anions ”, where together with alpersite , bieberite , boothite , melanterite and zinc melanterite, the“ melanterite group ”with the system no. VI / C.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 classifies mallardite in the category of "sulfates (selenates, etc.) without additional anions, with H 2 O". However, this is further subdivided according to the relative size of the cations involved , so that the mineral is classified in the subdivision “B. With only medium-sized cations ”is to be found, where the“ melanterite group ”with the system number is also found together with alpersite, bieberite, boothite, melanterite and zinc melanterite. 7.CB.35 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns mallardite to the class of "sulfates, chromates and molybdates" and there in the department of "water-containing acids and sulfates". Here it is also in the " melanterite group (heptahydrate, monoclinic: P 2 1 / c ) " with the system no. June 29, 2010 to be found in the subsection “Water-based acids and sulfates with AXO 4 × x (H 2 O)”.
Chemism
In chemically pure form, which can only be achieved with the synthetically produced compound Mn [SO 4 ] · 7H 2 O , mallardite contains 19.83% manganese , 11.57% sulfur , 63.51% oxygen and 5.09% Hydrogen . Mallardite produced naturally usually contains various foreign admixtures . For example, magnesium and / or calcium admixtures were detected in analyzed samples from the Lucky Boy Mine in the USA and from the Jokoku Mine near Kaminokuni on the Japanese island of Hokkaidō .
Crystal structure
Mallardite crystallizes monoclinically in the space group P 2 1 / c (space group no. 14) with the lattice parameters a = 14.15 Å ; b = 6.50 Å; c = 11.06 Å and β = 105.6 ° and 4 formula units per unit cell .
The crystal structure consists of isolated manganese (H 2 O) 6 - octahedra and SO 4 - tetrahedra , which are linked by hydrogen bonds to form a framework. The seventh H 2 O molecule is not bound to the manganese cations.
properties
Mallardite, like most sulphates, is water-soluble. In the air it loses its crystal water relatively quickly and finally disintegrates into powder.
With a Mohs hardness of ≈ 2, mallardite is one of the soft minerals that, like the reference mineral gypsum , scratch with the fingernail.
Education and Locations
Mallardite is secondary to the weathering (oxidation) of Fe-Mn sulfides and carbonates in a climate saturated with moisture. Depending on the locality, he can in this case with various other minerals associated occur as among other Alabandite , Chvaleticeit , Copiapit , Epsomite , gypsum , Ilesit , Jokokuit , Kutnohorit , manganese content calcite and Melanterite, rhodochrosite and Rozenite .
In addition to its type locality , the Lucky Boy Mine , the mineral occurred in Utah in the Bingham Canyon Mine southwest of Salt Lake City. In addition, it was only found in the United States in the Lake Valley in the Sierra County of New Mexico.
In Europe, Mallardit is still known from Markirch (Sainte-Marie-aux-Mines) in the French department of Haut-Rhin, from the Grotta del Vetriolo near the spa town of Levico Terme in Trentino in Italy and from Jáchymov ( Sankt Joachimsthal ) and Chvaletice ( Chwaletitz ) in the Czech region of Bohemia.
Other sites known to date (as of 2018) are Broken Hill in the Australian state of New South Wales, Kaminokuni on the Japanese island of Hokkaidō , Cerro de Pasco in the Peruvian region of Pasco, the first cinder cone of the Tolbachik volcano in the Far East of Russia and the Minas de Riotinto in the Spanish province of Huelva (Andalusia).
See also
literature
- Ad. Carnot: Note on un nouveau sulfate de manganèse naturel (Mallardite) . In: Bulletin de la Société Minéralogie de France . tape 2 , no. 1 , 1879, p. 117 ( upmc.fr [PDF; 11.4 MB ; accessed on April 16, 2018]).
- Richard V. Gaines, H. Catherine W. Skinner, Eugene E. Foord, Brian Mason , Abraham Rosenzweig: Dana's New Mineralogy . 8th edition. John Wiley & Sons, New York (et al.) 1997, ISBN 0-471-19310-0 , pp. 612 .
- Matsuo Nambu, Katsutoshi Tanida, Tsuyoshi Kitamura, Euchi Kato: Mallardite from the Jokoku mine, Hokkaido, Japan . In: Journal of the Japanese Association of Mineralogists, Petrologists & Economic Geologists . tape 74 , no. 11 , 1979, pp. 406–412 ( rruff.info [PDF; 458 kB ; accessed on April 17, 2018]).
Web links
- Mineral Atlas: Mallardite (Wiki)
Individual evidence
- ↑ Hans Jürgen Rösler : Textbook of Mineralogy . 4th revised and expanded edition. German publishing house for basic industry (VEB), Leipzig 1987, ISBN 3-342-00288-3 , p. 683 .
- ↑ a b c d e 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. 383 .
- ↑ a b Webmineral - Mallardite
- ↑ a b c d e f g h Mallardite . 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; 67 kB ; accessed on April 16, 2018]).
- ↑ a b c d Mindat - Mallardite
- ↑ Richard V. Gaines, H. Catherine W. Skinner, Eugene E. Foord, Brian Mason , Abraham Rosenzweig: Dana's New Mineralogy . 8th edition. John Wiley & Sons, New York (et al.) 1997, ISBN 0-471-19310-0 , pp. 612 .
- ^ Friedrich Klockmann : Klockmanns textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke, Stuttgart 1978, ISBN 3-432-82986-8 , pp. 607 (first edition: 1891).
- ↑ Find location list for mallardite in the Mineralienatlas and in Mindat