Sometimes called the poor man's opal, it does look someting like a cross between opal and mother of pearl. It is a rather soft stone with an internal luminscence, frequently blue or purple, although there is a varient called a 'peach moonstone' that somewhat resembles a sunstone.

Symbolic of, naturally, everything to do with the moon and all her properties. Often used in ritual to represent the Goddess because of its feminine associations. Moonstone stands for left, silver, water, air, moon, female, receptive energy, healing, spiritual aspects.