sorry, I can't answer your question about whether any glass sink can be an undermount, but know the make them specifically for that installation. I think you have to be sure that it's opaque so you don't see the plumbing. But I would be more worried about the possibility of the sink cracking or shattering at some point and having to replace it. I assume you'd have to lift off the counter to replace it, but maybe I'm wrong and it can be done from inside the cabinet? I am one of several here who have had a glass vessel sink crack or shatter and I don't think I'd recommend them.

It would definitely be opaque. Appreciate your feedback on the cracking. Consumer Reports said that dropping metal (like scissors or nail clippers) could do that but that they held up well otherwise. You've given me some more to think about.

If you do a google search you will see many instances of spontaneously exploding glass sinks (and glass shower doors/enclosures) - even when no one is in the room. Mine was fine for almost a year, then when I was running hot water in it, it cracked. And it was a very thick glass, not something skimpy. I'm replacing it soon (it doesn't leak, just looks bad) but decided against glass again.

Hello,
That's what I wanted in my little bathroom but wanted a granite countertop and, after seeing some cracking problems,opted for a traditional almond sink to match my tub etc.I got a bright, busy granite as my focal and kept
the rest of the room neutral. I put DECOR PLASTIC as my shower surround - it looks like stone (if you use your imagination) but is very durable. If anyone is interested, I'll try to figure out how to post a few pics when I'm done.
Thanks so much to all of you who share you opinions and experinces.

Brickeyee, I didn't mean to imply it was tempered - but the many sinks and shower doors that have exploded seem to have been. Just pointing out to op the risks of breakage for glass besides dropping something on it: cracking or exploding.