Okenite, CaSi2O . 5 . 2H2O ( simplistic formula ) is a silicate mineral often found together with zeolites in basalt geodes. The origin of this specimen is unknown, but it is probably from Poona in India. The "cotton ball" effect is created by thousands of fine fibrous crystals radiating from a central point. The individual crystals, although fragile, have a degree of flexibility. The very pale green colour of the mineral surrounding the okenite, suggests that it is probably another silicate mineral, prehnite.