Wardit
| Wardit | |
|---|---|
 |
|
| General and classification | |
| other names |
Soumansit ( Sousmansite ) |
| chemical formula | NaAl 3 [(OH) 4 | (PO 4 ) 2 ] • 2H 2 O |
|
Mineral class (and possibly department) |
Phosphates, arsenates and vanadates |
|
System no. to Strunz and to Dana |
8.DL.10 ( 8th edition : VII / D.13) July 42, 2008-02 |
| Crystallographic Data | |
| Crystal system | tetragonal |
| Crystal class ; symbol | tetragonal-trapezoidal; 422 |
| Space group | P 4 1 2 1 2 (No. 92) or P 4 3 2 1 2 (No. 96) |
| Lattice parameters | a = 7.03 Å ; c = 19.04 Å |
| Formula units | Z = 4 |
| Frequent crystal faces | {010}, {011}, {012}, {100}, rarely also {001} |
| Physical Properties | |
| Mohs hardness | 5 |
| Density (g / cm 3 ) | measured: 2.81 to 2.87; calculated: 2.805 |
| Cleavage | completely after {001} |
| colour | colorless, white, light green, blue-green, light yellow, yellow-green, brown |
| Line color | White |
| transparency | transparent to opaque |
| shine | Glass gloss |
| Crystal optics | |
| Refractive indices |
n ω = 1.586 to 1.594 n ε = 1.595 to 1.604 |
| Birefringence | δ = 0.009 |
| Optical character | uniaxial positive |
Wardite is a rarely occurring mineral from the mineral class of " phosphates , arsenates and vanadates ". It crystallizes in the tetragonal crystal system with the composition NaAl 3 [(OH) 4 | (PO 4 ) 2 ] · 2H 2 O, so it is chemically a basic sodium - aluminum phosphate.
Wardit mostly develops dipyramidal, pseudo-octahedral crystals up to about four centimeters in size, the surfaces of which have a glass-like sheen and often a characteristic striation at right angles to the c-axis . In its pure form, the mineral is transparent and colorless. However, it can appear white due to lattice construction errors or due to multiple light refraction in the case of multicrystalline formation and, due to foreign admixtures, it can take on a light green to blue-green, light yellow to yellow-green or brown color, the transparency decreasing accordingly. However, the line color is always white.
With a Mohs hardness of 5, wardite is one of the medium-hard minerals that, like the reference mineral apatite , can just be scratched with a knife.
Etymology and history
Wardit was first discovered in the Cedar Valley of the Clay Canyon near Fairfield in the Oquirrh Mountains in the US state of Utah. It was first described in 1896 by John M. Davison, who named the mineral after Henry Augustus Ward (1834-1906).
The synonym Soumansit or Sousmansite arose due to a mineral find in the French community Soumans (Limousin region), which was described in 1910 by Antoine Lacroix in his work Minéralogie de la France et des ses colonies . However, recent studies have shown that this mineral is identical to wardite and therefore the name Sousmansite has been discredited.
classification
Already in the outdated 8th edition of the mineral classification according to Strunz , wardite belonged to the mineral class of "phosphates, arsenates and vanadates" and there to the department of "water-containing phosphates, arsenates and vanadates with foreign anions ", where it gave its name to the "wardite series." “With the system no. VII / D.13 and the other members Cyrilovit and Millisit ( Pallit ).
In the Lapis mineral directory according to Stefan Weiß, which, out of consideration for private collectors and institutional collections, is still based on this old form of Karl Hugo Strunz's system , the mineral was given the system and mineral number. VII / D.51-10 . In the "Lapis system" this also corresponds to the section "Hydrous phosphates with foreign anions", where Wardit, together with Cyrilovite, Fluorowardit and Millisit, forms an independent but unnamed group (as of 2018).
The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and was updated by the International Mineralogical Association (IMA) until 2009, also assigns wardite to the category of “phosphates etc. with 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 other anions to the phosphate, arsenate or vanadate complex (RO 4 ), so that the mineral can be classified according to its composition in the sub-section “With large and medium-sized cations ; (OH etc.): RO 4 = 2: 1 ”can be found where the“ Warditgruppe ”with the system no. 8.DL.10 and the other members Cyrilovit and Millisit.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , also assigns the wardite to the class of "phosphates, arsenates and vanadates" and there in the category of "water-containing phosphates, etc., with hydroxyl or halogen". Here it is together with Cyrilovite in the " Cyrilovite group " with the system no. July 42, 2008 within the sub-section “Phosphates containing water, etc., with hydroxyl or halogen with (AB) 5 (XO 4 ) 3 Z q × x (H 2 O)”.
Crystal structure
Wardite is one of the few minerals that crystallizes with tetragonal trapezoidal symmetry and is therefore of particular interest in crystallography . It is the only mineral that has only four folding axes in symmetry. Wardite crystallizes in the space group P 4 1 2 1 2 (space group no. 92) or P 4 3 2 1 2 (no. 96) with the lattice parameters a = 7.03 Å and c = 19.04 Å as well as 4 formula units per Unit cell .
Education and Locations
Wardite is formed as a conversion product of amblygonite in phosphate-containing deposits and pegmatites . There he usually occurs in paragenesis with Variscit , but can also Crandallit , Eosphorit , Fairfieldit , Ferrisicklerit , Hydroxylherderit , Millisit , Mitridatit , Montgomeryit , Roscherit , siderite and / or Whitlockit be found associated.
As a rare mineral formation, Wardite has only been found at a few sites so far; around 50 sites are known. In addition to its type locality Clay Canyon, the mineral occurred in the United States at Lucin ( Box Elder County ) and at Amatrice ( Stansbury Mountain Range , Tooele County ) in Utah; in the "Stewart Mine" in San Diego County , California ; in the Strickland pegmatite near Portland , Connecticut; at Two Top Creek in Fremont County , Idaho; at several locations in Main , New Hampshire and South Dakota .
In Austria, Wardit has so far been found in several places on Lake Millstatt and Wolfsberg in Carinthia and on Höllkogel near Freßnitzgraben in Styria.
Rapid Creek in the Dawson mining area in the Canadian Yukon Territory , where many rich specimens and perfect crystals several centimeters in size have been found, is also worth mentioning for its exceptional wardite finds .
Other locations include Argentina, Australia, Belgium, Brazil, Finland, France and Spain.
literature
- Paul Ramdohr , Hugo Strunz : Klockmann's textbook of mineralogy . 16th edition. Ferdinand Enke Verlag, 1978, ISBN 978-3-432-82986-9 , pp. 653 .
Web links
- Mineral Atlas: Wardite
- Wardite search results. In: rruff.info. Database of Raman spectroscopy, X-ray diffraction and chemistry of minerals (RRUFF), accessed on May 22, 2019 .
Individual evidence
- ↑ a b c d e Hugo Strunz , Ernest H. Nickel : Strunz Mineralogical Tables. Chemical-structural Mineral Classification System . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p. 516 (English).
- ↑ Webmineral - Wardite (English)
- ↑ a b c d Wardite . 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 May 22, 2019]).
- ↑ a b c d Wardite. In: mindat.org. Hudson Institute of Mineralogy, accessed May 22, 2019 .
- ↑ John M. Davison: Wardite: a new hydrous basic phosphate of alumina . In: The American Journal of Science . tape 2 , no. 7-12 , 1896, pp. 154–155 (English, rruff.info [PDF; 201 kB ; accessed on May 22, 2019]).
- ^ A. Lacroix: Minéralogie de la France et des ses colonies . tape 5 . Paris 1910, p. 541 (French).
- ↑ Pete J. Dunn, Michael Fleischer, George Y. Chao, Louis J. Cabri, Joseph A. Mandarino: New Mineral Names . In: American Mineralogist . tape 68 , no. 11-12 , 1983, pp. 1252 (English, minsocam.org [PDF; 638 kB ; accessed on May 22, 2019] Discredited Mineral: Sousmansite (= Wardite)).
- ↑ Stefan Weiß: The large Lapis mineral directory. All minerals from A - Z and their properties. Status 03/2018 . 7th, completely revised and supplemented edition. Weise, Munich 2018, ISBN 978-3-921656-83-9 .
- ↑ Ernest H. Nickel, Monte C. Nichols: IMA / CNMNC List of Minerals 2009. (PDF 1816 kB) In: cnmnc.main.jp. IMA / CNMNC, January 2009, accessed February 23, 2020 .
- ↑ Wardit in Mineralien-Lexikon, Retrieved on August 1, 2011 ( Memento of the original from January 28, 2016 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Mindat - Number of localities for Wardit
- ↑ Petr Korbel, Milan Novák: Mineral Encyclopedia . Nebel Verlag GmbH, Eggolsheim 2002, ISBN 3-89555-076-0 , p. 187 ( Dörfler Natur ).
- ↑ Mindat - Gallery of Warditen from Rapid Creek, Dawson Mining District, Yukon Territory, Canada
