Contribution
Properties of alabandite; alabandite from Finland
Törnroos, Ragnar
Neues Jahrbuch für Mineralogie - Abhandlungen Band 144 Heft 1 (1982), p. 107 - 123
23 références bibliographiques
publié: Jun 1, 1982
DOI: 10.1127/njma/144/1982/107
ArtNo. ESP154014401005, Prix: 29.00 €
Abstract
Alabandite has been discovered from three mineralisations in Finland: 1) Associated with rhodochrosite and kutnahorite (a new mineral for Finland) in highly metamorphosed Precambrian sediments in Vittinki. 2) Associated with sphalerite, pyrite, pyrrhotite and galena in sphalerite-bearing layers in phyllitic and calcareous schists in Pattijoki. 3) Associated with sphalerite, pyrite, pyrrhotite, chalcopyrite, pentlandite, galena, ullmanite, gudmundite and stannite in slightly metamorphosed black schists in Sotkamo, and filling the space between fibres in tremolite in black carbonate layers in Sotkamo. The iron content of the alabandite in Vittinki is 0.7 w-%, in Pattijoki 4.0-6.2 w-%, and in Sotkamo 4.2-7.0 w-%. The physical properties of alabandite change when the iron content increases: the unit cell dimension decreases, but the Vickers Hardness Number (VHN), density and reflectance increase. At an iron content of 4-5 w-% the internal colour (colour of translucent parts, internal reflections) changes from green to red or brown.
Mots-clefs
Alabandite • Fe • concentration • lattice constant • reflectance • hardness • density • microprobe analysis • mineral association • Finland (Vittinki • Pattijoki • Sotkamo)