Okenite, CaSi2O. 5 . 2H2O is a colourless silicate mineral that is closely associated with zeolites. The cotton wool effect of this mineral is the result of very fine fibrous radiating crystals. This specimen is from the Poona district in India, probably from Malad quarry in Mumbai. Deccan lava flows in the late cretaceous period which deposited massive areas of basalt, are the source of this mineral. Also visible on this specimen around the Okenite are what are possibly small globular crystals of Gyrolite.