Lanarkit
| Lanarkit | |
|---|---|
 |
|
| General and classification | |
| other names |
|
| chemical formula | Pb 2 [O | SO 4 ] |
|
Mineral class (and possibly department) |
Sulfates (and relatives) |
|
System no. to Strunz and to Dana |
7.BD.40 ( 8th edition : VI / B.13) 02/30/01/01 |
| Crystallographic Data | |
| Crystal system | monoclinic |
| Crystal class ; symbol | monoclinic prismatic; 2 / m |
| Space group | C 2 / m (No. 12) |
| Lattice parameters |
a = 13.75 Å ; b = 5.70 Å; c = 7.07 Å β = 115.8 ° |
| Formula units | Z = 4 |
| Physical Properties | |
| Mohs hardness | 2 to 2.5 |
| Density (g / cm 3 ) | measured: 6.92; calculated: 7.08 |
| Cleavage | completely after {201}, indistinct after {401}, indistinct after {201} |
| Break ; Tenacity | splintery |
| colour | greenish-white, gray, gray-white, yellow, light yellow |
| Line color | White |
| transparency | transparent to translucent |
| shine | Diamond luster, pearlescent luster, resin luster |
| Crystal optics | |
| Refractive indices |
n α = 1.928 n β = 2.007 n γ = 2.036 |
| Birefringence | δ = 0.108 |
| Optical character | biaxial negative |
| Other properties | |
| Special features | fluorescent |
Lanarkite is a rarely occurring mineral from the mineral class " sulfates ( and relatives )". It crystallizes in the monoclinic crystal system with the chemical composition Pb 2 [O | SO 4 ] and develops mostly prismatic crystals stretched in the direction of the b-axis ([010]) in greenish-white, gray-white, gray, yellow to light yellow color with a white line color.
Etymology and history
Lanarkit was first discovered in the south of the former county of Lanarkshire , more precisely in the "Susanna Mine" at Leadhills .
The mineral was described in 1832 by François Sulpice Beudant , who named it after its type locality .
classification
In the meanwhile outdated, but still in use 8th edition of the mineral classification according to Strunz , the lanarkite belonged to the mineral class of "sulfates, selenates, tellurates, chromates, molybdates, tungstates" and there to the department of "anhydrous sulfates with foreign anions ", where it belongs together formed an independent group with Grandreefit , Leadhillit , Macphersonit , Olsacherit , Pseudograndreefit and Susannit .
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 the Lanarkit to the class of "sulfates (selenates, tellurates, chromates, molybdates and wolframates)" and there in the department of “Sulphates (selenates etc.) with additional anions, without H 2 O”. However, this section is further subdivided according to the size of the cations involved , so that the mineral can be found according to its composition in the sub-section “With only large cations”, where it is the only member of the unnamed group 7.BD.40 .
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the Lanarkit to the class of "sulfates, chromates and molybdates" and there to the category of "anhydrous sulfates with hydroxyl or halogen". Here he is the only member of the unnamed group 02/30/01 within the subdivision of " Anhydrous sulfates with hydroxyl or halogen with (AB) 2 XO 4 Z q ".
Crystal structure
Lanarkite crystallizes monoclinically in the space group C 2 / m (space group no. 12) with the lattice parameters a = 13.75 Å ; b = 5.70 Å; c = 7.07 Å and β = 115.8 ° as well as 4 formula units per unit cell .
properties
From a chemical point of view, lanakit is a lead sulfate . Its Mohs hardness is between 2 and 2.5 and its density is 6.92 g / cm 3 .
Under long-wave UV light and under X-rays , some lanarkites show a yellow fluorescence .
Education and Locations
As a typical secondary mineral , lanarkite is preferably formed in lead ore deposits . It is accompanied by various lead minerals such as galena , from which it can also be formed through weathering.
As a rare mineral formation, lanarkite could only be detected in a few places, whereby around 100 sites have been documented (as of 2019).
Well-known sites are among others in New South Wales and South Australia in Australia ; Baden-Württemberg , Lower Saxony and North Rhine-Westphalia in Germany ; Salzburg , Styria and Tyrol in Austria ; Bohemia in the Czech Republic ; as well as Arizona , Missouri and Utah in the USA .
See also
Web links
- Mineral Atlas: Lanarkit (Wiki)
- David Barthelmy: Lanarkite Mineral Data. In: webmineral.com. Retrieved February 27, 2019 .
Individual evidence
- ↑ a b Royal Bavarian Academy of Sciences (ed.): Scholar advertisements . tape 3 , no. 184 . Central-Schulbücher-Verlag, Munich 1836, p. 425 ( limited preview in Google Book Search [accessed February 27, 2019]).
- ↑ Armand Dufrénoy : Handbook for determining the minerals in a dichotomous way: after Dufrénoy's Traité de Minéralogie . Verlag der Schweiger Buchhandlung, Clausthal 1848, p. 104 ( limited preview in Google Book Search [accessed February 27, 2019]).
- ↑ a b c d e Hugo Strunz , Ernest H. Nickel: Strunz Mineralogical Tables . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X .
- ↑ a b Lanarkite . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America . 2001 (English, handbookofmineralogy.org [PDF; 65 kB ; accessed on February 27, 2019]).
- ↑ a b c d Lanarkite. In: mindat.org. Hudson Institute of Mineralogy, accessed February 27, 2019 .
- ↑ Localities for Lanarkite. In: mindat.org. Hudson Institute of Mineralogy, accessed February 27, 2019 .
- ↑ List of localities for lanarkite in the Mineralienatlas and Mindat