Hephaistosite

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Hephaistosite
General and classification
other names

IMA 2006-043

chemical formula TlPb 2 Cl 5
Mineral class
(and possibly department) 		Halides
System no. to Strunz
and to Dana 		3.AA.60
05/11/08/02
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  = 8.9477 (6)  Å ; b  = 7.9218 (7) Å; c  = 12.4955 (5) Å
β  = 90.092 (4) °
Formula units Z  = 4
Frequent crystal faces {010}, {101}, {100}, {001}, {011}, {110}
Physical Properties
Mohs hardness Please complete!
Density (g / cm 3 ) calculated: 5.93
Cleavage Please complete!
colour light yellow
Line color Please complete!
transparency transparent
shine Please complete!

Hephaistosite is a very rare mineral from the mineral class of halides with the chemical composition TlPb 2 Cl 5 and is therefore chemically a thallium - lead - chloride .

Hephaistosite crystallizes in the monoclinic crystal system and develops tabular crystals of up to 0.1 mm in size and green-yellow in color.

Etymology and history

The mineral was first found in 2008 by Italo Campostrini, Francesco Demartin, Carlo Maria Gramaccioli and Paolo Orlandi in the crater La Fossa on the Italian island of Vulcano . They named it after the Greek god of fire and blacksmithing Hephaestus , who, according to myth, had his workshop on Vulcano.

classification

In the systematics of minerals according to Strunz , hephaistosite is classified among the simple halides. In the 9th edition it forms with challacolloite a subgroup of the simple halides without crystal water and a ratio of metal to halide of 1: 1 or 2: 3.

In the systematics of minerals according to Dana it forms the challacolloite group with challacolloite, steropesite and panichiite, a subgroup of the complex halides - aluminum fluorides with a general composition (A) m B (X) 6 .

Crystal structure

Hephaistosite crystallizes in the monoclinic crystal system in the space group P 2 1 / c (space group no. 14) with the lattice parameters a  = 8.95  Å ; b  = 7.92 Å, c  = 12.50 Å and β = 90 ° 09 'as well as four formula units per unit cell . Template: room group / 14

Modifications and varieties

With challacolloite, hephaistosite forms a series of mixed crystals in which thallium is exchanged for potassium .

Education and Locations

Hephaistosite forms in fumaroles at high temperatures of around 400 ° C and was found in a pyroclastic breccia , associated with bismuthhinite , challacolloite , cotunnite and pseudocotunnite .

The only known site for hephaestosite is its type locality La Fossa on Vulcano.

See also

literature

  • Italo Campostrini, Francesco Demartin, Carlo Maria Gramaccioli, Paolo Orlandi: Hephaistosite, TlPb 2 Cl 5 , a new thallium mineral from La Fossa crater, Vulcano, Aeolian Islands, Italy . In: The Canadian Mineralogist . tape 46 , no. 3 , 2008, p. 701–708 , doi : 10.3749 / canmin.46.3.701 .
  • D. Mitolo, D. Pinto, A. Garavelli, L. Bindi, F. Vurro: The role of the minor substitutions in the crystal structure of natural challacolloite, KPb2Cl5, and hephaistosite, TlPb 2 Cl 5 , from Vulcano (Aeolian Archipelago, Italy) . In: Minerogy and Petrology . tape 96 , 2009, p. 121-128 , doi : 10.1007 / s00710-008-0041-2 .

Web links

Individual evidence

  1. ^ IMA / CNMNC List of Mineral Names; September 2017 (PDF 1.67 MB)
  2. ↑ a b Italo Campostrini, Francesco Demartin, Carlo Maria Gramaccioli, Paolo Orlandi: Hephaistosite, TlPb 2 Cl 5 , a new mineral thallium from La Fossa crater, Vulcano, Aeolian Islands, Italy . In: The Canadian Mineralogist . tape 46 , no. 3 , 2008, p. 701–708 , doi : 10.3749 / canmin.46.3.701 .
  3. ↑ a b Hephaistosite . 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; 43  kB ; accessed on November 6, 2017]).
  4. ↑ Find location list for Hephaestosit in the Mineralienatlas and Mindat