Even when glass breaks, it never really goes away unless it is ground up. When pieces of glass, from bottles, plates, or other containers end up in the ocean or in other bodies of water, they become weathered. The term for pieces of glass that have been exposed to the water is sea glass or beach glass.
Sea glass has been in the ocean and is usually very weathered by the salt and the waves.
Beach glass is basically the same thing as sea glass, however the pieces of glass are found in bodies of freshwater.
Sea glass and beach glass are smooth around the edges, which is nice because they cannot cut you. There are many beautiful colors of sea glass and beach glass. Part of the fun when it comes to beach glass and sea glass is hunting for the glass.
If you visit the Sea Glass Journal you can find lots of information about sea glass, beach glass, and all the things related to this neat type of glass.