Roman and Byzantine are the two mosaic styles known today. In the Byzantine tradition mosaics were made of colored glass, gold and Mother of Pearl which gave them an incomparable beauty. This was, without doubt, the most significant moment for mosaics.

Small peices of glass or marble, called "tessera," are used to build a mosaic. Marble tessera is much harder and more suited for floor mosaics, while glass tessera offer a larger variety of colors.

Artistic "tessera" are still produced by hand on the island of Murano (near Venice, Italy), home of the artistic mosaic glass. Colors are melted directly into the glass, which is flattened out and cooled down and finally cut into many small pieces. The work is done entirely by hand, thus making the glass tessera extremely valuable.