These Bisazza 20mm x 20mm x 4mm Italian vitreous mosaic glass tiles are simply the best you can buy. 

And we sell our tiles loose - so there's no need to mess around soaking them off the paper!

The tiles are bevelled, flat on one side and ridged on the reverse (to accept the adhesive) and are fired at far higher temperatures than the cheap Chinese versions normally sold on craft sites. These makes them harder, more frost resistant and easier to cut. They are approximately 4mm thick.

To achieve the gold effect the molten glass is sprinkled with granules of the quartz avveturina.