Tuesday, August 24, 2010

⤱ Gypsum ⤱

Gypsum is a very soft calcium sulphate mineral that can be scratched with a fingernail, and is also water-soluble. It may occur as colourless transparent crystals with a high lustre, "rams's horn" curved crystals, and fishtail twins. It has a formula of Ca(SO4).2H2O.

This specimen is from Bicker's Quarry, a basalt quarry near Tokatoka, Northland, North Island, New Zealand.