We need to know more. Can you scratch it with your fingernail, a regular nail, another rock...does it scratch glass. Does it break easily, do you see any bubbles in the structure of the mineral. Is it brittle? Does it react with an acid,? (be careful to use safety equipment to protect your eyes and skin and to test it in a well ventilated area). Where did you find it? Like I found it near a river in Chapel Hill, North Carolina.