Zapatalite

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Zapatalite
Zapatalite-185524.jpg
Zapatalite from the Miguel Vacas Mine, Pardais, Vila Viçosa , Évora, Portugal
General and classification
other names

IMA 1971-023

chemical formula Cu 3 Al 4 [(OH) 3 | PO 4 ] 3 • 4H 2 O
Mineral class
(and possibly department) 		Phosphates, arsenates and vanadates
System no. to Strunz
and to Dana 		8.DE.20 ( 8th edition : VII / D.20)
42.05.03.01
Similar minerals Chrysocolla , Shattuckite , Turquoise
Crystallographic Data
Crystal system tetragonal
Crystal class ; symbol not defined
Lattice parameters a  = 15.22  Å ; c  = 11.52 Å
Formula units Z  = 6
Physical Properties
Mohs hardness 1.5
Density (g / cm 3 ) measured: 3.016; calculated: 3.017
Cleavage good after {001}
colour light blue to turquoise blue
Line color Light Blue
transparency translucent
shine frosted
Crystal optics
Refractive indices n ω  = 1.646
n ε  = 1.635
Birefringence δ = 0.011
Optical character uniaxial negative

Zapatalite is a very rare mineral from the mineral class of " phosphates , arsenates and vanadates ". It crystallizes in the tetragonal crystal system with the composition Cu 3 Al 4 [(OH) 3 | PO 4 ] 3 · 4H 2 O, so it is chemically a water-containing copper - aluminum phosphate.

Zapatalite mainly develops massive or kidney to grape-like mineral aggregates and crack fillings from light blue to turquoise blue color with light blue streak color .

Etymology and history

Zapatalite was found for the first time in a small prospecting field northwest of Cerro Morita and about 27 kilometers southwest of Agua Prieta in the Mexican state of Sonora .

The mineral was scientifically described and named after the well-known Mexican revolutionary leader Emiliano Zapata in 1971 by Sidney A. Williams , who submitted his results and the chosen name to the International Mineralogical Association (IMA) for examination of the mineral status. The application received the registration number IMA 1971-023 and was recognized in the same year. The research results and the recognized name were published in Mineralogical Magazine in March of the following year .

Type material of the mineral is in the Natural History Museum in London, England under the register no. 1972,174 as well as in the National Museum of Natural History in Washington DC, USA under the register no. 135060 kept.

classification

In the meanwhile outdated, but still in use 8th edition of the mineral classification according to Strunz , the zapatalite belonged to the mineral class of "phosphates, arsenates and vanadates" and there to the department of "water-containing phosphates with foreign anions ", where it belongs together with chalcophyllite , cerulite , leogangite , Lirokonit and Parnauit formed a separate group.

The 9th edition of Strunz's mineral systematics , which has been in force since 2001 and is used by the International Mineralogical Association (IMA), assigns zapatalite to the class of “phosphates, arsenates and vanadates” and there to the department of “phosphates, etc. with additional anions; with H 2 O “. However, this section is further subdivided according to the size of the cations involved and their molar ratio to the phosphate, arsenate or vanadate complex, so that the mineral can be classified according to its composition in the sub-section “With only medium-sized cations; (OH etc.): RO 4  = 3: 1 “can be found where it is the only member of the unnamed group 8.DE.20 .

The systematics of minerals according to Dana also assigns zapatalite to the class of "phosphates, arsenates and vanadates" and there to the category of "water-containing phosphates etc., with hydroxyl or halogen". Here he is to be found as the only member of the unnamed group May 42, 2003 within the subdivision of " Water-containing phosphates etc., with hydroxyl or halogen with (A) 2 (XO 4 ) Z q × x (H 2 O) ".

Education and Locations

Zapatalite forms secondarily in the oxidation zone of hydrothermal deposits with silicified, breccia- like limestone , mainly in paragenesis with libethenite , pseudomalachite and chrysocolla .

So far (as of 2011), zapatalite has been detected at around 10 sites worldwide. In addition to its type locality Cerro Morita in Sonora, Mexico, the mineral was also found in the "Spring Creek Mine" near Wilmington in the Australian state of South Australia ; near Brixlegg in the Austrian district of Kufstein ; in the "Miguel Vacas Mine" near Vila Viçosa in Portugal as well as in Snowstorm Mountain in Elko County and Battle Mountain in Lander County in the USA.

Crystal structure

Zapatalite crystallizes tetragonally, but the space group has not yet been determined. The lattice parameters are a  = 15.22  Å and c  = 11.52 Å and 6 formula units per unit cell .

See also

literature

Web links

Commons : Zapatalite  - collection of images, videos and audio files

Individual evidence

  1. ↑ 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.  505 .
  2. ↑ a b Zapatalite , in: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 63.4 kB )
  3. ↑ a b c Mindat - Zapatalite (English)