Hidalgoit

Hidalgoit
	Pastel green, kidney hidalgoite aggregate from the Gold Hill Mine, Deep Creek Mountains, Tooele County , Utah, USA ( overall size : 6.4 cm × 5.2 cm × 2.7 cm)
General and classification
chemical formula	PbAl 3 [(OH) 6 \| SO 4 \| AsO 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) ; 04/43/01/03
Crystallographic Data
Crystal system	trigonal
Crystal class ; symbol	ditrigonal-scalenohedral; 3 2 / m
Space group	R 3 m (No. 166)
Lattice parameters	a = 7.04 Å ; c = 16.99 Å
Formula units	Z = 3
Physical Properties
Mohs hardness	4.5
Density (g / cm 3 )	measured: 3.71 to 3.96; calculated: 4.15 to 4.27
Cleavage	not defined
Break ; Tenacity	uneven to shell-like; brittle
colour	white, light green, pistachio green, emerald green
Line color	White
transparency	translucent
shine	frosted
Crystal optics
Refractive indices	n ω = 1.713 to 1.730 ; n ε = 1.715 to 1.735
Optical character	uniaxial positive

Hidalgoit is a rarely occurring mineral from the mineral class of " phosphates , arsenates and vanadates ". It crystallizes in the trigonal crystal system with the chemical composition PbAl ₃ [(OH) ₆ | SO ₄ | AsO ₄ ], so it is a lead - aluminum - sulfate arsenate with additional hydroxide ions .

Hidalgoit is mainly found in the form of granular to compact, porcelain-like or porous masses and crack fillings. Small, spherulitic or kidney mineral aggregates are also known. Hidalgoit also very rarely develops microscopic crystals with a scalenohedral habit . In its pure form, hidalgoite is colorless and transparent. However, due to its polycrystalline formation, it is usually translucent white or takes on a light green, pistachio green or emerald green color due to foreign admixtures.

Etymology and history

Hidalgoit was first discovered in the "San Pascual Mine" near Zimapán ( Municipio Zimapán ) in the Mexican state of Hidalgo and described in 1953 by Robert L. Smith, Frank S. Simons and Angelina C. Vlisidis, who named the mineral after the state in which its type locality is.

The type material of the mineral is in the Mines ParisTech ( École des mines de Paris ) in France and at Harvard University in Cambridge, Massachusetts (Katelog No. 106373-106375) and in the National Museum of Natural History in Washington, DC (catalog No. 112726, 112727) in the USA.

classification

In the outdated, but partly still in use, 8th edition of the mineral classification according to Strunz , the hidalgoite belonged to the mineral class of "phosphates,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 , Hinsdalit , Kemmlitzit , Orpheit , Schlossmacherit , Svanbergit and Woodhouseit the "Beudantit-Gruppe" 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 hidalgoite to the category 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 other 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 and large cations; (OH etc.): RO ₄ = 3: 1 “can be found, where together with Beudantite, Corkite, Gallobeudantite, Hinsdalite, Kemmlitzite, Orpheit, Svanbergite, Weilerite and Woodhouseit 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 area , assigns the hidalgoit to the class of "phosphates, arsenates and vanadates" and there in the department of "phosphates". Here he is also in the "Beudantit group" with the system no. 43.04.01 within the subsection " Compound phosphates etc., (anhydrous compound anions with hydroxyl or halogen) ".

Crystal structure

Hidalgoit crystallizes trigonal in the space group R 3 m (space group no. 166) with the lattice parameters a = 7.04 Å and c = 16.99 Å as well as three formula units per unit cell . Template: room group / 166

Education and Locations

Rare, colorless to white, granular hidalgoite aggregate from the Sauberg mine, Ehrenfriedersdorf , Ore Mountains, Saxony (field of view: 3 mm)

Light brownish hidalgoite in matrix from the Gold Hill Mine, Deep Creek Mountains, Tooele County , Utah, USA (size: 6.4 cm × 4.5 cm)

Hidalgoite formed secondarily in the oxidation zone of polymetallic sulfide - deposits . As accompanying minerals may include Beudantit , Carbonatcyanotrichit , limonite , Mansfieldit and various tourmalines occur.

As a rare mineral formation, Hidalgoit could only be detected at a few sites, with around 60 sites being known to date (as of 2014). Its type locality "San Pascual Mine" in Hidalgo is the only known site in Mexico so far.

In Germany, Hidalgoit was able to work in the “Michael” mine near Weiler and the “Silbereckle” mine near Reichenbach (Lahr) in the Black Forest in Baden-Württemberg; near Gadernheim and at Grauen Stein near Wiesbaden-Frauenstein in Hesse; in the Caspari antimony mine near Uentrop (Arnsberg) , near Ramsbeck , in the Plöger quarry near Velbert , the United Glückauf mine near Rösrath and “Genna Zinkhütte” near Letmathe in North Rhine-Westphalia; in the Friedrichssegen mine near Bad Ems / Lahnstein in Rhineland-Palatinate and the “Sauberg” mine near Ehrenfriedersdorf in Saxony.

In Switzerland, the mineral is so far only known from Mürtschenalp in the canton of Glarus .

Other locations are in Australia, Belgium, Chile, China, France, Greece, Ireland, Italy, Japan, Namibia, Portugal, Spain, the Czech Republic, the United Kingdom (UK) and the United States of America (USA).

literature

Robert L. Smith, Frank S. Simons, Angelina C. Vlisidis: Hidalgoite, a new mineral. In: American Mineralogist. Volume 38 (1953), pp. 1218–1224 ( PDF 410.2 kB )
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. 676 .
Friedrich Klockmann : Klockmann's textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke, Stuttgart 1978, ISBN 3-432-82986-8 , pp. 604 (first edition: 1891).

Web links

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

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. 462 .
↑ ^a ^b ^c Hidalgoite , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 62 kB )
↑ Mindat - picture example of a crystal lawn from Hidalgoit
↑ Mindat - Number of localities for Hidalgoite
↑ Find location list for Hidalgoit at the Mineralienatlas and at Mindat

[StrunzNickel-1] 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. 462 .

[Datenblatt-2] Hidalgoite , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 62 kB )

[Mindat-481436-3] Mindat - picture example of a crystal lawn from Hidalgoit

[MindatAnzahl-4] Mindat - Number of localities for Hidalgoite

[Fundorte-5] Find location list for Hidalgoit at the Mineralienatlas and at Mindat