Manjiroite
| Manjiroite | |
|---|---|
 |
|
| General and classification | |
| other names |
IMA 1966-009 |
| chemical formula | Na (Mn 4+ 7 Mn 3+ ) O 16 |
|
Mineral class (and possibly department) |
Oxides and hydroxides |
|
System no. to Strunz and to Dana |
4.DK.05a ( 8th edition : IV / D.08) 07.09.01.03 |
| Crystallographic Data | |
| Crystal system | tetragonal |
| Crystal class ; symbol | tetragonal-dipyramidal, 4 / m |
| Space group | I 4 / m (No. 87) |
| Lattice parameters | a = 9.916 Å ; b = 2.864 Å |
| Formula units | Z = 1 |
| Physical Properties | |
| Mohs hardness | 4th |
| Density (g / cm 3 ) | measured: 4.29; calculated: 4.45 |
| Cleavage | Please complete |
| colour | dark brownish gray; yellowish gray-white in reflected light |
| Line color | brownish black |
| transparency | opaque |
| shine | frosted |
| Crystal optics | |
| Optical character | uniaxial |
| Other properties | |
| Chemical behavior | soluble in hydrochloric acid (HCl) |
Manjiroite is a rare mineral belonging to the mineral class of oxides and hydroxides . The mineral crystallizes in the tetragonal crystal system with the chemical composition Na (Mn 4+ 7 Mn 3+ ) O 16 . It forms compact crystals up to 10 cm in size.
Etymology and history
The mineral was discovered in 1967 by Japanese researchers Matsuo Nambu and Katsutoshi Tanida. They named it after the Japanese mineralogist and geologist Manjiro Watanabe (1891–1980). This was a professor at Tōhoku University in Sendai , Japan.
classification
In the outdated, but still in use 8th edition of the minerals according to Strunz , the mineral is classified in the mineral class of oxides and hydroxides. This is further subdivided according to the ratio of metal to oxygen , so that the mineral can be found in the group "Metal to oxygen 1: 2 (MO 2 and related compounds)" according to its composition . There it can be found with Cesàrolith , Coronadit , Henrymeyerit , Hollandit , Kryptomelan , Mannardit , Priderit , Redledgeit and Strontiomelan in the cryptomelan group . The also associated mineral Ankangit was stripped of its independence in 2012, since then it has also fallen under Mannadite.
In the 2001 published and comprehensively revised 9th edition of the minerals according to Strunz , which is also used by the International Mineralogical Association (IMA), manjiroite is also classified in the mineral class of oxides and hydroxides. As in the 8th edition, this is further subdivided according to the ratio of metal to oxygen, so that the mineral can be found in the group "Metal to oxygen 1: 2 and comparable" according to its composition. This is, however, further subdivided according to the size of the cations involved , and since manganese and sodium belong to the medium-sized cations, it can be found in the corresponding subgroup “With large (and medium-sized) cations; Tunnel structures ". There it forms akaganeite those Coronadit, Henrymeyerit, Hollandit, manjiroite, Mannardit, Priderit and Redledgeit Hollanditgruppe . Ankangit would also belong here, had it not been deprived of its independence in favor of Mannadit, as the variety of which it is now listed.
In the systematics of minerals according to Dana , which is mainly used in English-speaking countries , the Manjiriot is also in the class of oxides and hydroxides. There it can be found in the group of "multiple oxides" (No. 07). This group is further subdivided, the mineral can be found in the subgroup also named here cryptomelane group with system number 07.09.01. The mineral here has the system number 07.09.01.03 .
Chemism
The chemical formula is not entirely clear. The Handbook of Mineralogy of the Mineralogical Society of America gives the formula (Na, K) (Mn 4+ , Mn 2+ ) 8 O 16 • nH 2 O due to the addition of potassium . In doing so, they largely follow Nambu and Tanida, who specify the formula (Na, K) Mn 4+ 8 O 16 • nH 2 O with n <2 in their first description . The CNMNC , on the other hand, speaks of Na (Mn 4+ 7 Mn 3+ ) O 16 in its list of minerals (as of September 2014) . It is not clear whether the manganese should really be in the +3 oxidation state. The Database of Raman spectroscopy , however, like the Handbuch der Mineralogie , speaks of the oxidation state +2. The chemical analysis of the Handbook of Mineralogy also speaks of up to 4% crystal water , which is also ignored by the CNMNC formula.
Education and Locations
Manjiroite is often found in conjunction with pyrolusite , nsutite , birnessite , cryptomelan, goethite and romanechite .
Manjiroite has been detected so far on 16 (as of January 2015). The type locality is in Japan in the province of Tōhoku , there in the prefecture of Iwate in Karumai in the Kohare mine. Otherwise there are sites in the Republic of the Congo , Germany , Portugal , Romania , Russia in the Ural Federal District , in South Africa and in the US states of Arizona , Colorado and New Jersey .
Crystal structure
Manjiroite crystallizes tetragonally in the space group I 4 / m (space group no. 87) with the lattice parameters a = 9.916 Å and c = 2.864 Å and 1 formula unit per unit cell .
See also
Web links
Individual evidence
- ↑ a b c The new list of minerals of the CNMNC , as of September 2014
- ↑ a b c d e f g h i manjiroite. In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, and Monte C. Nichols (Eds.): Handbook of Mineralogy , Mineralogical Society of America , 2001 ( PDF , English)
- ↑ a b c d e f Mineralienatlas: Manjiroit
- ^ A b c Matsuo Nambu, Katsutoshi Tanida: Manjirōite, a new manganese dioxide mineral, from Kohare Mine, Iwate Prefecture, Japan. In: The Journal of the Japanese Association of Mineralogists, Petrologists and Economic Geologists , Vol. 58, No. 2, 1967, pp. 39–54 ( PDF , Japanese with English abstract)
- ↑ Database-of-Raman-spectroscopy - Manjiroite (English)
- ↑ Mindat - Manjiroit (English)