Ca3(PO4)2  Can be added to porcelain to make bone china - bone china is non-plastic, unstable in the kiln and difficult to fire consistenlty due to a very narrow firing range. Up to 2% bone ash can be used in enamles for opacification - more will create pinholes. Too long a firing or too high a temperature will result in blisters. Not suitable for slip casting. Glass jar is for illustration purposes only.