Gypsum is an evaporite mineral with the formula CaSO4 . 2H2O , calcium sulphate dihydrate. This specimen was collected from the beach cliffs at Blue Anchor bay, Watchet, in west Somerset. The cliffs are Triassic in age, and are alternating layers of green marl and red keuper marl. There are many veins of gypsum running through the cliffs, and this specimen was collected from a vein in the red marl. The top and bottom of the specimen are fairly solid, and in between weathering has taken place revealing the original growth of gypsum as it was evaporated from saline water.