Yes you may. If the glass is thinner it sometimes helps to pad out the glass tile's location by applying a thin coat of thinset on the subfloor where the glass tile will be set, and let it cure.

Then come back the next day and set the glass tiles flush with the surrounding field tiles with more thinset.

If the glass tile is translucent, use white thinset so the gray color of regular gray thinset doesn't muddle the blue color of the glass tile.

Well, I'm guessing the glass tiles are blue...

Hmmm, where in the beautiful blue skies did you get that idea?

Blue
Owner of blue granite kitchen and bath countertops
Thermador with blue knobs
Believes that Blue (color) is superior to Not-Blue (color)