Malhmoodit
| Malhmoodit | |
|---|---|
 |
|
| General and classification | |
| other names |
|
| chemical formula | FeZr [PO 4 ] 2 • 4H 2 O |
|
Mineral class (and possibly department) |
Phosphates, arsenates and vanadates |
|
System no. to Strunz and to Dana |
8.CE.75 ( 8th edition : VII / C.09) 01/40/05/01 |
| Crystallographic Data | |
| Crystal system | monoclinic |
| Crystal class ; symbol | monoclinic prismatic; 2 / m |
| Space group | P 2 1 / c (No. 14) |
| Lattice parameters |
a = 9.12 Å ; b = 5.42 Å; c = 19.17 Å β = 94.8 ° |
| Formula units | Z = 4 |
| Physical Properties | |
| Mohs hardness | ≈ 3 |
| Density (g / cm 3 ) | calculated: 2.877 |
| Cleavage | Please complete |
| colour | creamy white |
| Line color | White |
| transparency | transparent to translucent |
| shine | Silky gloss |
| Crystal optics | |
| Refractive indices |
n α = 1.640 n β = 1.652 n γ = 1.652 |
| Birefringence | δ = 0.012 |
| Optical character | biaxial negative |
Malhmoodite , formerly also known as Mahlmoodite , is an extremely rare mineral from the mineral class of "phosphates, arsenates and vanadates". It crystallizes in the monoclinic crystal system with the chemical composition FeZr [PO 4 ] 2 · 4H 2 O and is therefore, from a chemical point of view, an iron - zirconium - phosphate containing water .
Malhmoodite is transparent to translucent and develops fibrous to needle-like or strip-shaped crystals of a creamy white color up to about 0.15 millimeters in length, which are usually arranged in radial mineral aggregates . Due to the iridescent effects of the closely spaced crystals in the aggregate forms, mineral samples of Malhmoodite usually have a silk-like sheen .
Etymology and history
Malhmoodite was first discovered in the Union Carbide Vanadium Mine near Wilson Springs in Garland County , Arkansas, and described by Charles Milton , James J. McGee, Howard T. Evans Jr., who named the mineral after Bertha K. Malhmood to honor her years of service as Executive Assistant to the United States Geological Survey's analytical laboratories .
The mineral was recognized as an independent mineral in 1992 by the International Mineralogical Association (IMA), however, initially under the false name Mahlmoodit , as the first person describing it had made a typo in its publication. This error was only corrected in 2002 by an official note from the Commission on New Minerals, Nomenclature and Classification (CNMNC).
The type material of the mineral is kept in the National Museum of Natural History in Washington, DC in the USA (Catalog No. 170394).
classification
Already in the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , malhmoodite belonged to the mineral class of "phosphates, arsenates and vanadates" and there to the department of "water-containing phosphates without foreign anions ", where together with Kolbeckite , Koninckit , Mansfieldite , metavariscite , parascorodite , phosphosiderite , scorodite , strictite , variscite and yanomaite the "variscite group" with the system no. VII / C.09 formed.
The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and is used by the IMA, also assigns Malhmoodite 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 ions to the water of crystallization content, so that the mineral is classified in the subsection “With only medium-sized cations; RO 4 : H 2 O ≤ 1: 2.5 “can be found, where it forms the unnamed group 8.CE.75 together with Zigrasit .
The systematics of minerals according to Dana , which is mainly used in the English-speaking area , assigns the Malhmoodite to the class of "phosphates, arsenates and vanadates" and there in the department of "water-containing phosphates etc.". Here he is to be found as the only member / together with in the unnamed group 40.01.05 within the subdivision "Water-containing phosphates etc., with A 2+ B 2+ (XO 4 ) × x (H 2 O)".
Crystal structure
Malhmoodite crystallizes monoclinically in the space group P 2 1 / c (space group no. 14) with the lattice parameters a = 9.12 Å ; b = 5.42 Å; c = 19.17 Å and β = 94.8 ° and 4 formula units per unit cell .
Education and Locations
Malhmoodite forms as a secondary mineral in cavities ( geodes ) of alkaline volcanic rocks . As Begleitminerale occur among others anatase , Kolbeckit , pyrite , sodium-containing pyroxene and sphalerite on.
In addition to its type locality , the Union Carbide Vanadium Mine and the associated “North Wilson” shaft near Wilson Springs, which are also the only known sites in the United States of America , the mineral is only known from the Kerriack (as of 2015) -Cave at Portreath in the English county of Cornwall.
See also
literature
- Charles Milton , James J. McGee, Howard T. Evans, Jr.: Mahlmoodite, FeZr (PO 4 ) 2 · 4H 2 O, a new iron zirconium phosphate mineral from Wilson Springs, Arkansas. In: American Mineralogist Volume 78 (1993), pp. 437–440 ( PDF 452 kB )
Web links
Individual evidence
- ↑ a b c d 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. 482 .
- ↑ a b c Mahlmoodite , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 65.8 kB )
- ↑ 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 .
- ↑ a b Webmineral - Malhmoodite
- ↑ a b c d Mindat - Malhmoodite
- ↑ Charles Milton , James J. McGee, Howard T. Evans, Jr. Mahlmoodite, FeZr (PO 4 ) 2 · 4H 2 O, a new iron zirconium phosphate mineral from Wilson Springs, Arkansas. In: American Mineralogist Volume 78 (1993), pp. 437–440 ( PDF 452 kB )
- ^ Joel D. Grice, Giovanni Ferraris: New minerals approved in 2002 and nomenclature modifications approved in 1998-2002 by the Commission on the New Minerals and Mineral Names, International Mineralogical Association. In: The Canadian Mineralogist Volume 41 (2003), pp. 795–802 ( PDF 42.8 kB )
- ↑ Find location list for Malhmoodite in the Mineralienatlas and in Mindat