The Mediterranean Artists Company has been making jewelry from ancient roman glass for decades. 

The glass fragments they use date back between the first and sixth centuries. They stabilize the glass fragments and shape them to make jewelry. They are like opals in that they appear differently under different lighting conditions and they have a wide range of colors that show themselves differently as the jewelry moves.

NOTE: The pictures do not do justice to the colors and and individualized nature of each of these pieces of jewelry. If you like the picture, you will LOVE the jewelry in person.