This definitely looks ceramic to me. If you are interested in a similar tile in glass instead of ceramic we carry one called 'cobalt' that would look very similar to this. I would get a few samples of a few blue tiles to make sure you are getting the look you want. Here is a link to it: http://www.subwaytileoutlet.com/products/Cobalt-Glass-Subway-Tile.html If we can help with anything please feel free to contact us.