Gypsum, sedimentary,  Penarth.

Gypsum, sedimentary, Penarth.

These specimens  of  gypsum, CaSO4 . 2H2O  were collected on the  same day. Both  had  eroded from the cliff face on Penarth beach, in South Wales. The rocks exposed on Penarth beach are Trassic Keuper  marls, the upper parts of which  Have  nodules of gypsum which were deposited from evaporation in a playa environment.  Both specimens are the same size. One is massive gypsum with a hint of pink, and one seems to be a collection of fragments deposited on more structured layers. These are specimens which should probably be included in my rock collection, which may be put online at some time.