Wakabayashilit
| Wakabayashilit | |
|---|---|
 |
|
| General and classification | |
| other names |
IMA 1969-024 |
| chemical formula | [(As, Sb) 6 S 9 ] [As 4 S 5 ] |
|
Mineral class (and possibly department) |
Sulfides and sulfosalts |
|
System no. to Strunz and to Dana |
2.FA.40 ( 8th edition : II / F.03) 11/02/04/01 |
| Crystallographic Data | |
| Crystal system | orthorhombic |
| Crystal class ; symbol | orthorhombic-pyramidal; mm 2 |
| Room group (no.) | Pna 2 1 (No. 33) |
| Lattice parameters | a = 25.262 Å ; b = 14.563 Å; c = 6.492 Å |
| Formula units | Z = 4 |
| Physical Properties | |
| Mohs hardness | ~ 1.5 |
| Density (g / cm 3 ) | measured: 3.96; calculated: 4.06 |
| Cleavage | completely according to {100}, {010}, {10 1 } |
| Break ; Tenacity | flexible |
| colour | golden to lemon yellow |
| Line color | orange yellow |
| transparency | translucent |
| shine | Silk gloss to resin gloss |
Wakabayashilite is a rarely occurring mineral from the mineral class of " sulfides and sulfosalts ". It crystallizes in the orthorhombic crystal system with the chemical composition [(As, Sb) 6 S 9 ] [As 4 S 5 ], so it is chemically an arsenic - antimony sulfide.
Wakabayashilit usually develops translucent crystals with a fibrous to prismatic habit up to about two centimeters in length, which are stretched parallel to the b-axis. The color varies between a warm gold tone and a strong lemon yellow. On the other hand, the mineral leaves an orange-yellow line on the marking board . Individual crystals have a resin-like sheen on their surfaces , while larger aggregates with closely spaced crystal fibers have a silky shimmer .
With a Mohs hardness of around 1.5, wakabayashilite is one of the soft minerals that can be scratched with the fingernail, similar to the reference minerals talc (1) and plaster of paris (2) if they are sufficiently large .
Etymology and history
Wakabayashilite was first discovered in the "Nishinomaki Mine" in the Japanese prefecture of Gunma and described in 1970 by A. Kato, K. Sakurai and K. Ohsumi, who named the mineral after the Japanese mineralogist of the Mitsubishi Mining Company Yaichiro Wakabayashi (1874–1943) .
classification
In the now outdated, but still common 8th edition of the mineral classification according to Strunz , the wakabayashilite belonged to the mineral class of "sulfides and sulfosalts" and there to the department of "non-metallic sulfides", where it formed an independent group with Getchellite .
The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), assigns wakabayashilite to the class of “sulfides and sulfosalts”, but in the newly defined section of “sulfides of arsenic, alkalis; Sulphides with halides, oxides, hydroxides, H 2 O “. This division is further subdivided according to the predominant elements in the compound, so that the mineral can be found according to its composition in the sub-division "with As, (Sb), S", where it is the only member of the unnamed group 2.FA. 40 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the wakabayashilite to the class of "sulphides and sulphosalts" and there in the category of "sulphide minerals". Here he is the only member of the unnamed group 11/02/04 within the subsection “ Sulphides - including selenides and tellurides - with the composition A m B n X p , with (m + n): p = 2: 3 ”.
Education and Locations
Wakabayashilite fine fibers is likely to form in the form in quartz - Druze or calcite and besides this even with realgar , orpiment , stibnite , pyrite and other sulphide minerals associated to find.
As a rare mineral formation, wakabayashilite could only be proven at a few sites. So far (as of 2011) around 15 sites are known, the type locality "Nishinomaki Mine" in Gunma prefecture is the only known site in Japan so far.
Other locations are the “La Coipa Mine” near Diego de Almagro in the Chilean Región de Atacama , several locations in China (Guangxi Zhuang, Guizhou and Yunnan), on Mont Pelvoux near Valgaudemar in France, in the Lukhumi arsenic deposit near Mestia -Racha in Georgia, in the antimony-mercury deposit of Khaidarkan (Chaidarkan) in the Fergana Valley in the Kyrgyz Alai Mountains , in the Gal-Khaya arsenic-mercury-antimony deposit in the East Siberian Republic of Sakha (Yakutia) and at several locations in US state of Nevada , where the richest specimens to date with well-developed crystals several centimeters long were found in the “White Caps Mine” near Manhattan in Nye County .
Crystal structure
Wakabayashilite crystallizes orthorhombically in the space group Pna 2 1 (space group no. 33) with the lattice parameters a = 25.262 Å ; b = 14.563 Å and c = 6.492 Å and 4 formula units per unit cell .
See also
literature
- A. Kato, K. Sakurai, K. Ohsumi: Wakabayashilite (As, Sb) 11 S 18 , in: Introduction to Japanese Minerals Geological Survey of Japan , Volume 39 (1970), pp. 92-93 ( PDF 257.4 kB )
Web links
Individual evidence
- ↑ a b c d e Paola Bonazzi, Giulio I. Lampronti, Luca Bindi, Stefano Zanardi: Wakabayashilite, [(As, Sb) 6 S 9 ] [As 4 S 5 ]: Crystal structure, pseudosymmetry, twinning, and revised chemical formula , in: American Mineralogist , Volume 90 (2005), pp. 1108–1114 (English, PDF 241.4 kB )
- ↑ Webmineral - Wakabayashilite (English)
- ↑ Wakabayashilite , in: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 60.4 kB )
- ↑ Mindat - Number of localities for Wakabayashilit
- ↑ Mindat - list of localities for Wakabayashilit
- ↑ Mindat - picture gallery of various Wakabayashilites from the "White Caps Mine", Manhattan (Nevada)