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Download hereGENERAL DESCRIPTION
Roselite is a rare hydrated calcium, magnesium and cobalt arsenate that is very appreciated by collectors. Like erythrite, it is an indicator on the presence of cobalt.
Its crystals are sometimes lengthened but they are generally appeared as small spheres. The colour varies from pale pink to purple. It is the presence of the element divalent cobalt (Co2+) which gives this colour.
Broad roselite crystals were found in abundance in the higher part of the zone of oxidation of 2 Moroccan mines. In the district of Bou Azzer, it is commonly associated erythrite (Co3(AsO4)2 8H2O), talmessite (Ca2 Mg (AsO4)2 2H2O) and wendwilsonite (Ca2 Mg (AsO4)2 2H2O). Roselite forms a series with the latter, which is its magnesiferous equivalent. Their density makes it possible to distinguish them one from the other.
Some other roselite deposits are the Rappold and Daniel mines in Germany, the district of Bou Azzer in Morocco, the Talmessi mine in Iran. The majority of the samples of the collectors come from the Moroccan deposits.
The place of conservation of the type of this species (coming from the Rappold mine in Neustädtel, district of Schneeberg, Metallic Mountains ("Erzgebirge"), Saxony, Germany and published in 1824) is not known.
HISTORY : Species dedicated to Gustav Rose (1798-1873), German mineralogist
Species first described in 1824 by Serve-Dieu Abailard (or Armand) Lévy (1795-1841), French mineralogist
Type-locality: Mine Rappold, Schneeberg, Saxony, Germany
CHEMICAL FORMULA : Ca2 Co+2 (AsO4)2 2H2O
CRYSTAL SYSTEM : Monoclinic
COLOR : Light- to dark pink
DIAPHANIETY : Transparent to translucent
LUSTER : Vitreous
STREAK : Pale red
MORPHOLOGIE : Crystals sometimes elongated, more often spherical
HARDNESS : 3,5
CHEMICAL CLASS: 3,65
DENSITY : VII - Phosphates, arsenates and vanadates
GROUP : Roselite
STRUNZ CLASS BEFORE 2001 : 7/C.17-100
STRUNZ CLASS AFTER 2001 : 8.GG.10
