Roselite Locality: Bou Azzer, Bou Azzer District, Tazenakht, Ouarzazate Province , Souss-Massa-Draâ Region, Morocco ( Locality at mindat.org ) Picture width 2 mm. Collection and photograph Christian Rewitzer — Photo: Christian Rewitzer · CC BY-SA 3.0
Roselite
A rare rose-pink calcium-cobalt-magnesium arsenate described in 1825 from Schneeberg, Saxony.
Intro adapted from Wikipedia (CC BY-SA).
Roselite is an IMA-recognized mineral species in the arsenate class, with the chemical formula Ca₂Co(AsO₄)₂·2H₂O.
It crystallizes in the monoclinic crystal system (space group P2_1/c). It is a member of the Roselite structural group.
Key properties: Mohs hardness 3.5; specific gravity 3.46–3.74; Vitreous luster; refractive index 1.729; optically biaxial.
IMA symbol Rsl, grandfathered status — known before the IMA’s founding, named in 1824.
Found as a rare secondary mineral in cobalt-bearing hydrothermal mineral deposits.
It is found associated with Talmessite (Bou Azzer, Morocco).
The mineral was named to honor Gustav Rose (1798–1873), Professor of Mineralogy, University of Berlin, Berlin, Germany.