Roselite

Roselite is a rare mineral that was first described in 1825 and named after the German mineralogist Gustav Rose. It occurs in a cobalt-bearing hydrothermal environment and was associated with quartz and chalcedony veins at the type locality. The mineral crystallizes in a monoclinic crystal system and usually develops short prismatic crystals a few millimeters to just over a centimeter in length, but is also found as spherulitic or granular aggregates or embedded in geodes and druses. The color of the transparent to translucent crystals varies between light and dark pink to rose red depending on the cobalt content, and the higher the cobalt content, the darker. The pleochroism of roselite depends on the chemical composition, with darker pink-colored varieties with a higher cobalt content and lighter pink-colored varieties with a higher calcium and magnesium content.