Disclaimer: I have no knowledge about this item. Looks like old trade/tourist goods made in the orient. I obtained about 57 of them in a storage locker auction. I have not had it professionally tested so I don’t know what type of stone it is. Not translucent. Color dark brown. Double sided. Indoor/outdoor. Measurements 5/16 inch thick, 3.25 inch x 4.25 inch. 4.6 oz / 129 grams.