Woodhouse
| Woodhouse | |
|---|---|
 |
|
| General and classification | |
| chemical formula | CaAl 3 [(OH) 6 | SO 4 | PO 4 ] |
|
Mineral class (and possibly department) |
Phosphates, arsenates and vanadates |
|
System no. to Strunz and to Dana |
8.BL.05 ( 8th edition : VII / B.35) 43.04.01.08 |
| Crystallographic Data | |
| Crystal system | trigonal |
| Crystal class ; symbol | ditrigonal-scalenohedral; 3 m |
| Space group | R 3 m (No. 166) |
| Lattice parameters | a = 6.99 Å ; c = 16.39 Å |
| Formula units | Z = 3 |
| Physical Properties | |
| Mohs hardness | 4.5 |
| Density (g / cm 3 ) | measured: 3.01; calculated: 3.00 |
| Cleavage | completely after {0001} |
| colour | colorless, white, pink |
| Line color | White |
| transparency | transparent to translucent |
| shine | Glass gloss, pearlescent |
| Crystal optics | |
| Refractive indices |
n ω = 1.636 n ε = 1.647 |
| Birefringence | δ = 0.011 |
| Optical character | uniaxial positive |
Woodhouseit is a rarely occurring mineral from the mineral class of " phosphates , arsenates and vanadates ". It crystallizes in the trigonal crystal system with the composition CaAl 3 [(OH) 6 | SO 4 | PO 4 ], so chemically speaking it is a calcium - aluminum phosphate with additional sulfate - ([SO 4 ] 2− ) and hydroxide ions (OH - ).
Woodhouseit usually develops rhombohedral , pseudocubic crystals of a few millimeters in size with a glass-like luster on the surfaces (pearlescent also possible after the c-axis). In its pure form it 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 pink color, the transparency decreasing accordingly.
Etymology and history
Woodhouseit was first discovered in the "Champion Mine" in the White Mountains in the US state of California and described in 1937 by Dwight M. Lemmon, who named the mineral after the American mineralogist Charles Douglas Woodhouse (1888–1975).
classification
Already in the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , the Woodhouseit belonged to the class of "phosphates, arsenates and vanadates" and there to the department of "anhydrous phosphates, with foreign anions F, Cl, O, OH", where together with Beudantit , Corkit , Gallobeudantit , Hidalgoit , Hinsdalit , Kemmlitzit , Orpheit , Schlossmacherit and Svanbergit the "Beudantitgruppe" with the system no. VII / B.35 .
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 Woodhouseit to the department of “Phosphates etc. with additional anions; without H 2 O “. However, this is further subdivided according to the relative size of the cations involved and the molar ratio of the additional anions (OH etc.) to the phosphate, arsenate or vanadate complex (RO 4 ), so that the mineral can be classified in the sub-section “With medium-sized and large cations; (OH etc.): RO 4 = 3: 1 “can be found, where together with Beudantite, Corkite, Gallobeudantite, Hidalgoite, Hinsdalite, Kemmlitzite, Orpheit, Schlossmacherite, Svanbergite and Weilerite, the“ Beudantite group ”with the system no. 8.BL.05 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns Woodhouseit to the class of "phosphates, arsenates and vanadates" and there in the department of "phosphates". Here it is together with Beudantite, Corkite, Gallobeudantite, Hidalgoite, Hinsdalite, Kemmlitzite, Orpheit, Svanbergite and Weilerite in the unnamed group 43.04.01 within the subdivision of " Compound phosphates etc., (anhydrous compound anions with hydroxyl or halogen) " Find.
Crystal structure
Woodhouseit crystallizes trigonally in the space group R 3 m (space group no. 166) with the lattice parameters a = 6.99 Å and c = 16.39 Å as well as 3 formula units per unit cell .
Education and Locations
Woodhouseite formed by clayey conversion hydrothermally decomposed, tonmineralreicher rocks such as kaolin or mineral mixture such as smectites and illites and can be found either in andalusite - Lagerstätteen or in the hydrothermal veins of other ore deposits . It is seldom formed in caves as a conversion product of guano . As Begleitminerale can topaz , Augelith , Lazulith and / or pyrophyllite occur.
As a rare mineral formation, Woodhouseit has so far only been proven at a few sites, with around 40 sites being known. In addition to its type locality , the "Champion Mine" in the White Mountains in the state of California, the mineral occurred in the United States of America (USA) in some places in Colorado ( Boulder County , Conejos County and Rio Grande County ), on Graves Mountain in Lincoln County (Georgia) , in the "Algonquin Mine" near Philipsburg (Montana), in the "Tyrone Mine" in Grant County (New Mexico) , near Skytop near State College in Center County (Pennsylvania) and in the "Willis Mountain Mine" near Farmville in Buckingham County, Virginia.
In Austria, Woodhouseit was only found on the Kleiner Finagl and on the Leutachkopf in the Untersulzbachtal .
Other locations are in Argentina, Australia, Belgium, Bolivia, Brazil, Bulgaria, Chile, China, Indonesia, Italy, Japan, Canada, Kyrgyzstan, Norway, Romania, Russia, Sweden, Spain, Hungary and the Czech Republic.
See also
literature
- DM Lemmon: Woodhouseite, a new mineral of the beudantite group , in: American Mineralogist , Volume 22 (1937), pp. 939–948 ( PDF 583.7 kB )
Web links
- Mineral Atlas: Woodhouseit (Wiki)
- Webmineral - Woodhouse site
- Database-of-Raman-spectroscopy - Woodhouse
Individual evidence
- ↑ 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 , p. 461 .
- ↑ a b Woodhouse page, in: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 63.5 kB )
- ↑ a b c Mindat - Woodhouse side
- ↑ Mindat - Number of localities for Woodhouseit