I found this at the beach. I have no idea if it's a stone or glass. When I shine a light through it, it has a beautiful emerald-like color and is translucent. However, I really don't know what it's made of. But if it's something formed by a natural phenomenon, I'm sure it's extremely rare. It has been soaked in bleach for a day and then dried in the sun. If you are interested, if you know what this is, or if you are a collector who understands its value, please consider it.