Hannebachite

from Wikipedia, the free encyclopedia
Hannebachite
Hannebachite-283918.jpg
Tabular, colorless Hannebachite crystals (about 2.06 mm in size) from the type locality Hannebacher Ley
General and classification
other names

IMA 1983-056

chemical formula Ca 2 (SO 3 ) 2 · H 2 O
Mineral class
(and possibly department) 		Oxides and hydroxides - sulfites, selenites, tellurites
System no. to Strunz
and to Dana 		4.JE.10 ( 8th edition : IV / K.05)
02/34/05/01
Crystallographic Data
Crystal system orthorhombic
Crystal class ; symbol dipyramidal 2 / m 2 / m 2 / m
Space group Pbna
Lattice parameters a  = 6.473  Å ; b  = 9.782 Å; c  = 10.646 Å
Formula units Z  = 4
Physical Properties
Mohs hardness 3.5
Density (g / cm 3 ) 2.52
Cleavage perfectly
colour colorless
Line color White
transparency transparent
shine Glass gloss
Crystal optics
Refractive indices n α  = 1.596
n β  = 1.600
n γ  = 1.634
Birefringence δ = 0.038
Optical character biaxial positive
Axis angle 2V = 38 °

Hannebachite is a very rarely occurring mineral from the mineral class of oxides and hydroxides . It crystallizes in the orthorhombic crystal system with the chemical composition Ca 2 (SO 3 ) 2 · H 2 O and develops colorless to white crystals .

Etymology and history

The mineral was first found and described in 1985 by G. Hentschel, E. Tillmanns and W. Hofmeister. Hannebachit was first found and described in 1985. It was named after its type locality , the so-called Hannebacher-Ley in the municipality of Spessart between Hannebach and Wollscheid in the Eifel .

classification

In the now outdated, but still in use 8th edition of the mineral classification according to Strunz , the Hannebachite belonged to the department of "Sulphites, Selenites and Tellurites", where together with Allochalkoselite , Burnsite , Chloromenite , Georgbokiit , Gravegliait , Ilinskit , Orschallit , Parageorgbokitiit , Prewittittiit and Sophiit formed the unnamed group IV / K.05 .

The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), classifies Hannebachite in the extended division of “Antimonites, Bismuthites, Sulphites, Selenites, Tellurites”. However, this is further subdivided according to the specific type of compound, so that the mineral can be found according to its composition in the sub-division of " sulfites ", where it is the only member of the unnamed group 4.JE.10 .

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns Hannebachite, in contrast to Strunz's systematics, to the class of " sulfates , chromates and molybdates " and there to the category of "selenites, tellurites and sulfites". Here it can be found together with Gravegliait in the unnamed group 02/34/05 within the sub-section “ Selenites - Tellurites - Sulphites with A 2+ XO 3 × x (H 2 O) ”.

Education and Locations

Hannebachite formed in caves in volcanic melilite - nepheline - leucitite rocks. It is associated with calcite , aragonite , gypsum , barite , celestite , thaumasite , chabazite , Phillipsit , Gismondin , Whewellit and perovskite .

In addition to its type locality, Hannebachite was also found in Eschweiler and Hüsten in North Rhine-Westphalia , Birresborn and Hillesheim in Rhineland-Palatinate and Ronneburg in Thuringia , Bad Gleichenberg in Austria and Łaziska in Poland .

Crystal structure

Hannebachite crystallizes in the orthorhombic crystal system in the space group Pbna with the lattice parameters a = 6.473  Å , b = 9.782 Å and c = 10.646 Å as well as four formula units per unit cell .

See also

Individual evidence

  1. ↑ a b Hannebachit in: Anthony et al .: Handbook of Mineralogy , 1990, 1, 101 ( pdf ).
  2. ↑ Stefan Weiß: The large Lapis mineral directory . 4th edition. Christian Weise Verlag, Munich 2002, ISBN 3-921656-17-6
  3. ↑ G. Hentschel, E. and W. Hofmeister Tillmanns: Hannebachite, natural calciumsulfite hemihydrite, CaSO 3 · ½ H 2 O . In: New yearbook mineralogy monthly books. 1985, pp. 241-250 ( Abstract in American Mineralogist, p. 928 ; PDF; 1.1 MB).
  4. ^ Mindat - Hannebachite
  5. ↑ Hannebachit in: Anthony et al .: Handbook of Mineralogy , 1990, 1, 101 ( pdf ).

Web links

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