DIRK WIERSMA / SCIENCE PHOTO LIBRARY DIRK WIERSMA / SCIENCE PHOTO LIBRARY
Picromerite mineral. The mineral picromerite (or schoenite) is a hydrated potassium magnesium sulphate (K2.Mg(SO4)2.6[H2O]). Its crystal system is monoclinic and it usually occurs as white, opaque earthy or crustal precipitates, deposited as an evaporate in marine environments after prolonged evaporation. More rarely it forms well-faceted, blocky and prismatic crystals, opaque and earthy-white, and sometimes translucent. This sample, from potash mines near Neuhoff Ellers in Germany, is 33 centimetres across.
Model release not required. Property release not required.