In these last two replies, that's all well and good. But if you use a glass tile that's basically clear glass, and th back of the tile is painted to give it its color (very popular tile because it's the same thickness as most ceramic tiles), you're still going to have a problem chipping the back off, which will be very obvious if you don't use a glass blade.
One other comment with reference to installing glass. In my last post, I recommended the use of the 254 (or Multipurpose Pro from Lowes) in white to set the glass. Although either of those are still valid recommendations, there's a new thinset that Laticrete just came out with that's meant specifically for setting glass, called "Glass Adhesive". It addresses all the problems with respect to off color "white" thinsets (from OTHER manufacturers!

), as well as more "tack" to hang the sheets, and grab onto the back of the tiles.
Additionally, they also just came out with the next generation of Spectralock (the Pro Premium), making it a much easier product to use, thereby making it possible even for DIYers to get epoxy grout protection for their installations!
Really good "stuff"!