This specimen multiple cavities that are lined in small, magenta roselite crystals, collected from Morocco.
Roselite is a monoclinic mineral of the hydrated phosphates group, and has a chemical formula of Ca2Co(AsO4)2 · 2H2O. It gained its name not from the rose color that is generally exhibited by the mineral, but was in fact named in honor of a German mineralogist by the name of Gustav Rose. However, the name is quite fitting, for roselite typically displays a vitreous rose-red to pink color. Darker colored crystals have been known to frequently display marked color zoning due to variations in molecular composition.