Hureaulith
| Hureaulith | |
|---|---|
 |
|
| General and classification | |
| chemical formula |
|
|
Mineral class (and possibly department) |
Phosphates, arsenates and vanadates |
|
System no. to Strunz and to Dana |
8.CB.10 ( 8th edition : VII / C.04) 39.02.01.01 |
| Crystallographic Data | |
| Crystal system | monoclinic |
| Crystal class ; symbol | monoclinic prismatic; 2 / m |
| Room group (no.) | C 2 / c (No. 15) |
| Lattice parameters |
a = 17.59 Å ; b = 9.13 Å; c = 9.50 Å β = 96.7 ° |
| Formula units | Z = 4 |
| Physical Properties | |
| Mohs hardness | 3.5 |
| Density (g / cm 3 ) | measured: 3.15 to 3.19; calculated: 3.19 |
| Cleavage | good after {100} |
| colour | light pink to red-violet, amber, orange, red, white, gray |
| Line color | almost white |
| transparency | transparent to translucent |
| shine | Glass gloss |
| Crystal optics | |
| Refractive indices |
n α = 1.637 to 1.657 n β = 1.645 to 1.667 n γ = 1.649 to 1.671 |
| Birefringence | δ = 0.012 to 0.014 |
| Optical character | biaxial negative |
| Axis angle | 2V = 75 to 82 ° (measured); 70 to 84 ° (calculated) |
| Pleochroism | visible: X = colorless; Y = yellow to light pink; Z = reddish yellow to reddish brown |
Hureaulite is a rather seldom occurring mineral from the mineral class of “phosphates, arsenates and vanadates”. It crystallizes in the monoclinic crystal system with the idealized chemical composition Mn 2+ 5 (PO 3 OH) 2 (PO 4 ) 2 · 4H 2 O is so chemically seen a water-containing manganese - phosphate .
Hureaulite is transparent to translucent and develops mostly tabular to short prismatic crystals with a glass-like sheen on the surfaces, but also occurs in the form of fibrous or massive mineral aggregates . In its pure form, Hureaulite is colorless and transparent. However, due to multiple refraction due to lattice construction defects or polycrystalline training, it can also appear white or gray and, due to foreign admixtures, take on a light pink to red-violet, amber or orange to red color, the transparency decreasing accordingly.
Etymology and history
Hureaulite was first discovered together with heterosite at Les Hureaux near the municipality of Saint-Sylvestre in the French department of Haute-Vienne and described in 1825 by François Alluaud (1778–1866), who named the mineral after its type locality .
In older publications, the mineral name can often be found in the spelling Huréaulith (with acute ). However, this corresponds neither to the spelling of the name originally published by Aluaud nor to the specifications for mineral naming of the IMA, according to which minerals, which were named after a geographical location, must be ensured that the spelling of the name corresponds to that at the type locality. With the 2008 publication "Tidying up Mineral Names: an IMA-CNMNC Scheme for Suffixes, Hyphens and Diacritical marks", the different spellings of various minerals were adjusted and the spelling Huréaulith has since been discredited due to the superfluous diacritical mark .
classification
Already in the outdated but still partially in use 8th edition of the mineral classification by Strunz of Hureaulith belonged to the mineral class of "phosphates, arsenates and vanadates" and then to the Department of "water containing phosphates without foreign anions " where he along with Sainfeldite and Villyaellenit the "Hureaulith series" with the system no. VII / C.04 formed.
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 Hureaulith to the category of “phosphates, etc., without additional anions; with H 2 O “. However, this is further subdivided according to the relative size of the cations involved and the molar ratio of the phosphate, arsenate or vanadate complex (RO 4 ) to the water of crystallization content , so that the mineral can be classified in the sub-section “With only medium-sized cations; RO 4 : H 2 O = 1: 1 "can be found, where it is also named after the" Hureaulithgruppe "with the system no. 8.CB.10 and the other members Miguelromeroit , Nyholmit , Sainfeldit and Villyaellenit.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the Hureaulite to the class of "phosphates, arsenates and vanadates" and there in the department of "". Here he is also the namesake of the " Hureaulitgruppe " with the system no. 39.02.01 can be found in the subsection “ Hydrous acid phosphates etc., H 2 (AB) 5 (XO 4 ) 4 × x (H 2 O)”.
Education and Locations
Hureaulite is secondary to the weathering of primary phosphate minerals in complex granitic pegmatites . As accompanying minerals may include Dickinsonit , Eosphorit , Fairfieldit , heterosite , Kakoxen , Lithiophilit , Phosphosiderit , Rockbridgeite , Roscherit , Stewartit , Strengit , triphylite and Vivianit occur.
As a rather rare mineral formation, Hureaulite can sometimes be abundant at various sites, but overall it is not very common. So far (as of 2014) around 120 sites are known. In addition to its type locality Les Hureaux, the mineral was also found in France in some quarries near Chanteloube and Bessines-sur-Gartempe in the Haute-Vienne department (Limousin region).
In Germany, Hureaulith was found on the Hennenkobel ( Hühnerkobel ) in the Bavarian Forest, at Krennbruch in the Lower Bavarian district of Freyung-Grafenau and at Stützersdorf (Markt Tittling ) in the district of Passau, as well as in the pegmatites near Hagendorf and in a silver mine near Waidhaus in the Upper Palatinate district of Neustadt at the Waldnaab.
The only known site in Switzerland so far is the Ponte valley near Brissago TI in the canton of Ticino.
Shingus in Pakistan , where violet crystals up to five centimeters in diameter were discovered, is known for its unusual hureaulite finds .
Other locations include Argentina, Australia, Brazil, Finland, Japan, Kazakhstan, Madagascar, Morocco, Mozambique, Namibia, Norway, Poland, Portugal, Romania, Rwanda, Spain, South Africa, the Czech Republic and the United States of America (USA) .
Crystal structure
Hureaulith crystallizes monoclinically in the space group C 2 / c (space group no. 15) with the lattice parameters a = 17.59 Å ; b = 9.13 Å; c = 9.50 Å and β = 96.7 ° and 4 formula units per unit cell .
See also
literature
- LN Vauquelin: Analysis de l'huraulite, mineral trouvé dans la commune d'Hureaux. In: Annales de Chimie et de Physique. Volume 3 (1825), pp. 302–307 ( PDF 344.3 kB )
- F. Alluaud: Notices sur l'hétérosite, l'hureaulite (fer et manganèse phosphatés), et sur quelques autres minéraux du département de la Haute-Vienne , in: Anneles des Sciences Naturelles , Volume 8 (1826), p. 334– 354 ( PDF 703.3 kB , French)
- Friedrich Klockmann : Klockmann's textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke , Stuttgart 1978, ISBN 3-432-82986-8 , pp. 639 (first edition: 1891).
- 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. 640 .
Web links
- Mineral Atlas: Hureaulite (Wiki)
- Database-of-Raman-spectroscopy - Hureaulite
- American-Mineralogist-Crystal-Structure-Database - Hureaulite
Individual evidence
- ↑ a b IMA / CNMNC List of Mineral Names; January 2014 (PDF 1.5 MB)
- ↑ Stefan Weiß: The large Lapis mineral directory. All minerals from A - Z and their properties . 5th completely revised and supplemented edition. Weise, Munich 2008, ISBN 978-3-921656-70-9 .
- ↑ Webmineral - Hureaulite
- ^ A b c 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. 474 .
- ↑ Hureaulite , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 66.6 kB )
- ↑ a b c d Mindat - Hureaulite
- ^ Ernest H. Nickel , Joel D. Grice: The IMA Commission on New Minerals and Minerala Names: Procedures and Guidelines on Mineral Nomenclature , In: The Canadian Mineralogist , Volume 36 (1998); PDF 328 kB , from p. 8
- ^ Ernst AJ Burke: Tidying up Mineral Names: an IMA-CNMNC Scheme for Suffixes, Hyphens and Diacritical marks , In: Mineralogical Record , Volume 39, No. 2 (March – April 2008); PDF 2.7 MB
- ↑ Mindat - Number of localities for Hureaulith
- ↑ Petr Korbel, Milan Novák: Mineral Encyclopedia . Nebel Verlag GmbH, Eggolsheim 2002, ISBN 3-89555-076-0 , p. 174 ( Dörfler Natur ).
- ↑ Find location list for Hureaulith at the Mineralienatlas and at Mindat