Glass tile with visible mesh backing
Last time I remember reading something about glass tile, it was said that it's usually installed "backwards" as in "face plant in the thinset" and then you peeled off the backing, which was actually a fronting. This is because a mesh backing would be visible through the back of the glass tile.
I have some glass tile I found on ebay, and ordered samples. They look great, but the mesh looks like a "backer" mesh, not a "fronter" paper sort of thing. It doesn't appear, from the shape of the tiles, or the difficulty in peeling the mesh off the tile (I tried, and it didn't come off easily or in a single piece) that it's designed to go on face first.