Rock 365 : Day 15 : Selenite #365photos

Day 15 : A piece of "moon rock". Selenite literally means 'Of the Moon' and named after Selene, the Greek goddess of the Moon (the Roman equivalent of whom is Luna). This shouldn't be confused with the 'gem' moonstone which is feldspar.  Selenite is a variety of gypsum (calcium sulphate).  The sample here shows a 'leaf' like habit due to the twinned crystals growing upwards.  The sample is from SE Spain, part of the Messinian (~5.4 Ma) evaporite sequence formed during the 'Messinian Salinity Crisis' where the Mediterranean Sea was cut off from the Atlantic and started to dry up.