Can I use XTR to bond metal or stone to glass?

Yes.

XTR is much thinner than HXTAL so you have to be more careful about bonding disparate materials with it as it will make thinner joints than HXTAL.

You can allow XTR to sit and thicken up slightly in order to compensate for the difference in COE between the different materials, but be careful you don't leave it too long and allow it thicken up to the point where you cannot work with it.

HXTAL is generally better suited for working disparate materials than XTR.