Ceramic tile mosaic detail on Flickr – by annpar
Mosaic Art Source mosaic definition:
tesserae – small, usually square pieces of glass or other material used to make a mosaic. Their size generally ranges from a few millimetres to two centimetres long and five to ten millimetres thick. The term derives from the Greek word meaning “four-sided”. m.a.s. mosaic glossary
Vitreous Tile Mosaic detail – by pauldub
Mosaic Art Source mosaic definition:
vitreous tile
vitreous tile – square glass mosaic tiles most commonly 3/4″ x 3/4″ made in molds from glass paste. They have a smooth top but the bottom is keyed with ridges for better adhesion. m.a.s.mosaic glossary
Smalti mosaic detail on Flickr – Jef Poskanzer
Mosaic Art Source mosaic definition:
smalti
smalto (pl. smalti) – smalti is characterized by its dazzling range of brilliant opaque colors. Smalti is prepared by adding crystalline material (corpo) and coloured material (anima) to the colourless or coloured fused glass. Smalti is literally available in thousands of colors, is a very stable glass, easy to cut and very durable. m.a.s. mosaic glossary
Mosaic Art Source 
Where can we purchase some of these micromosaics. thank you George Long