Boothit

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Boothit
Arseniosiderite-Boothite-sea69b.jpg
Grainy aggregate of light blue boothite crystals, overgrown with light brown arseniosiderite from the Copper Basin, Lander County , Nevada ( overall size : 8.8 cm × 6.1 cm × 4.3 cm)
General and classification
other names

Copper sulfate heptahydrate

chemical formula Cu [SO 4 ] • 7H 2 O
Mineral class
(and possibly department) 		Sulphates (selenates, tellurates, chromates, molybdates and tungstates)
System no. to Strunz
and to Dana 		7.CB.35 ( 8th edition : VI / C.06)
06/29/10/02
Similar minerals Chalcanthite
Crystallographic Data
Crystal system monoclinic
Crystal class ; symbol monoclinic prismatic; 2 / m
Space group P 2 1 / c (No. 14)Template: room group / 14
Lattice parameters a  = 14.190 (10)  Å ; b  = 6.537 (2) Å; c  = 10.825 (6) Å
β  = 106.02 (5) °°
Formula units Z  = 4
Physical Properties
Mohs hardness 2 to 2.5
Density (g / cm 3 ) measured: 1.94
Cleavage imperfect after {001}
Break ; Tenacity uneven; brittle
colour Light Blue
Line color Light Blue
transparency transparent to translucent
shine Glass gloss, silk to pearlescent gloss
Crystal optics
Refractive indices n α  = 1.470
n β  = 1.480
n γ  = 1.490
Birefringence δ = 0.020
Optical character biaxial negative

Boothite is a very rarely occurring mineral from the mineral class of "sulfates (and relatives, see classification ") with the chemical composition Cu [SO 4 ] · 7H 2 O and is therefore chemically a water-containing copper (II) sulfate , more precisely its heptahydrate .

Boothite crystallizes in the monoclinic crystal system , but rarely develops well-formed crystals . It is mostly found in the form of coarse masses with a granular, crystalline to fibrous structure. The mineral is transparent to translucent and blue in color, although it is lighter than that of chalcanthite . The line color of Boothit is also light blue. Crystalline surfaces have a glass-like sheen , while fibrous aggregates tend to have a silk to mother-of-pearl sheen .

Etymology and history

Boothite was first discovered from the Alma Pit on the Leona Heights copper, gold and silver sulphide deposit in Alameda County , California. It was first described in 1903 by Waldemar Theodore Schaller , who named the mineral after the chemist Edward Booth (1857-1917).

Type material for Boothit is not defined.

classification

In the 8th edition of the mineral systematics according to Strunz , which is outdated but still in use , boothite belonged to the mineral class of "sulfates, chromates, molybdates, wolframates (including selenates and tellurates)" and there to the department "C. Water-containing sulfates, without foreign anions ”, where together with alpersite , bieberite , mallardite , melanterite and zinc melanterite, the“ melanterite group ”with system no. VI / C.06 .

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 classifies boothite in the category of "sulfates (selenates, etc.) without additional anions, with H 2 O". However, this is further subdivided according to the relative size of the cations involved , so that the mineral is classified in the subdivision “B. With only medium-sized cations ”is to be found, where the“ melanterite group ”with the system number is also found together with alpersite, bieberite, mallardite, melanterite and zinc melanterite 7.CB.35 forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns boothite to the class of "sulfates, chromates and molybdates" and there in the department of "water-containing acids and sulfates". Here it is also in the " melanterite group (heptahydrate, monoclinic: P 2 1 / c ) " with the system no. June 29, 2010 to be found in the subsection “Water-based acids and sulfates with AXO 4 × x (H 2 O)”.

Chemism

In the idealized, theoretical composition Cu [SO 4 ] · 7H 2 O, boothite contains 27.84% CuO., 28.02% SO 3 and 44.14% H 2 O. Analyzes of samples from the type locality Alma pit in Alameda County and from Campo Seco in the west of Calaveras County, however, showed small amounts of iron and magnesium . More recent analyzes of samples from the copper mines near Burraga in the Australian state of New South Wales also contained admixtures of zinc , manganese and cobalt , so that the newly defined empirical formula 2004 with (Cu 0.860 Mg 0.072 Zn 0.055 Mn 0.0l0 Co 0.003 ) Σ1,000 SO 4 · 7H 2 O was given.

Crystal structure

Boothite crystallizes monoclinically in the space group P 2 1 / c (space group no. 14) with the lattice parameters a  = 14.190 (10)  Å ; b  = 6.537 (2) Å; c  = 10.825 (6) Å and β = 106.02 (5) ° and 4 formula units per unit cell . Template: room group / 14

properties

Like most sulfates, boothite is water soluble.

In the air, Boothite loses its crystal water over time and finally changes into the less water-containing mineral chalcanthite . The dehydration can be accelerated when the mineral is heated to over 105 ° C.

Modifications and varieties

Greenish- blue cupromagnesite from Monte Somma , Italy (size: 2.0 cm × 2.0 cm × 2.0 cm)

Boothite varieties with a relevant proportion of magnesium (about 0.57%) or zinc (about 7.49%) are also referred to as Mg boothite and Zn boothite .

Magnesium-containing boothite is also known as cupromagnesite .

Education and Locations

Boothite is formed as a less stable weathering product from chalcopyrite at around 0 ° C. As Begleitminerale found at its type locality pit Alma, in addition to chalcopyrite, you still Chalkanthit , Melanterite and its variety Pisanit .

In addition to the Alma and Leona pits in the Leona Heights deposit near Oakland in Alameda County , at Campo Seco in Calaveras County, at Baker in San Bernardino County and at the Tunnel Ranch in Santa Barbara County in California, the mineral also joined in the United States Bisbee (Conchise County), in Laurel Canyon ( Graham County ) and Mayer ( Yavapai County ), Arizona; at Butte in Montana; in copper basin of Lander County in Nevada and in the uranium-copper deposit Deer Flat in White Canyon ( San Juan County on) in Utah.

In addition to the copper mines near Burraga (New South Wales), the mineral was also found in Australia in the Prince Lyell copper, gold and silver mine near Queenstown on the island of Tasmania .

In Europe, boothite has so far only been found in an iron mine in the commune of Sain-Bel and in a copper mine near Chessy in the French region of Auvergne-Rhône-Alpes and on Vesuvius in the Campania region and in the Grotta del Vetriolo near the spa town of Levico Terme can be found in Trentino in Italy. The locations of Evje (Flåt mine) and Kvinnherad (Hatlestrand mine) in Norway mentioned in other sources are incorrect or have not yet been confirmed.

Otherwise only the Mina Salvadora near Calama in the Chilean Región de Antofagasta and the volcano Tolbatschik on the Kamchatka Peninsula in Russia's Far East are known to have been found around the world.

See also

literature

  • Waldemar T. Schaller: Minerals from Leona Heights, Alameda Co., California . In: University of California Publications. Bulletin of the Department of Geology . tape 3 , 1903, pp. 191-217 .
  • FW Clarker, WF Hillebrand, FL Ransome, SL Penfield, Waldemar Lindgren, George Steiger, WT Schaller: Geological Survey Bulletin . tape 262 . US Department of the Interior, Geological Survey, Washington, DC 1905, p. 122–123 ( usgs.gov [PDF; 8.7 MB ; accessed on April 15, 2018]). ( limited preview in Google Book search)
  • C. Doelter, H. Leitmeier (Ed.): Handbuch der Mineralchemie . Sulphates, chromium, molybdenum, tungsten, uranium, haloid salts and salt deposits. 4, part two. Springer, Berlin, Heidelberg 1929, p. 288–290 ( limited preview in Google Book search).

Web links

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

Individual evidence

  1. ↑ a b Friedrich Klockmann : Klockmanns textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke, Stuttgart 1978, ISBN 3-432-82986-8 , pp.  607 (first edition: 1891).
  2. ^ A b c 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.  384 .
  3. ↑ a b Peter Leverett, Adam R. McKinnon, Peter A. Williams: New data for boothite, CuSO4 7H2O, from Burranga, New South Wales . In: Australian Journal of Mineralogy . tape 10 , no. 1 , June 2004, p. 3–6 ( abstract from researchdirect [accessed April 15, 2018]).
  4. ↑ a b c d e f g h i Boothite . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America . 2001 ( handbookofmineralogy.org [PDF; 63  kB ; accessed on April 9, 2018]).
  5. ↑ a b c Webmineral - Boothite
  6. ↑ a b c d Mindat - Boothite
  7. ↑ Type locality description Alma Mine at the Mineralienatlas and at Mindat
  8. ↑ a b C. Doelter, H. Leitmeier (Ed.): Handbuch der Mineralchemie . Sulphates, chromium, molybdenum, tungsten, uranium, haloid salts and salt deposits. 4, part two. Springer, Berlin, Heidelberg 1929, p. 288–290 ( limited preview in Google Book search).
  9. ↑ 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.  679 .
  10. ↑ Stefan Weiß: The large Lapis mineral directory. All minerals from A - Z and their properties . 6th completely revised and supplemented edition. Weise, Munich 2014, ISBN 978-3-921656-80-8 .
  11. ↑ List of locations for boothite in the Mineralienatlas and Mindat