Not true. There may be some, but most mosaics use about 7-10mm thick stone tile. I have seen a lot of them... They last because they are covered, and the better

Not true. There may be some, but most mosaics use about 7-10mm thick stone tile. I have seen a lot of them... They last because they are covered, and the better preserved are often in dry climates. Archeological sites tend to cover them back up with a layer of gravel to protect them.