Gypsum

Gypsum

Gypsum, CaSO4 . 2H2O is an evaporite mineral, commonly found in layered sedimenary rocks. The specimen is a Selenite variety of Gypsum known as " Satin Spar " It is 9cm. x 9cm. as per view and 7 cm. deep. Note the faint centerline  where the fibrous gypsum has grown inwards from two opposing walls to meet in the center. The location is loosely referred to as Nottingham