Sea glass and beach glass are pieces of glass worn smooth by waves. Technically, "Sea glass" is glass found on beaches along bodies of salt water. As the glass reaches the shoreline pounding waves and rocks break it into smaller pieces. The sharp edges are worn smooth. Salt water erodes the glass and gives it a frosted appearance. "Beach glass" comes from fresh water. It is found mainly along coastlines and the shores of large lakes. However many feel sea glass and beach glass are the same thing. 