This ring is made of a beautiful piece of black sea glass set in fine and sterling silver.

Black Sea glass (also called Pirate glass) is known to be some of the oldest sea glass, and it is quite possibly the hardest to find.  The actual colour can be seen when holding it up to the light, either very dark green or very dark brown... but on the shore it looks like a black pebble so most people walk right past it. It takes a trained eye to recognize it.