To tell the difference between Bone and Ivory Poker Chips, heat a needle (medium sized sewing needle will work) over a candle or flame until hot. Use the hot needle to pierce a small hole in the chip, then smell. If it smells like ‘burned hair’ it is BONE, if it has NO smell, it is Ivory. Ivory is also harder to penetrate with the hot needle than Bone. If you thought this was a helpful tip, please vote 'yes.'  Thank You, TheBreezeHouse