Above, you can see two sets of glass tile , those on the left are mass produced 'water glass tiles' and you can see the consistency of the size and shape. Because production technology is so good these days, these high quality colored glass tile fit well into modern, minimalist, high end bathrooms and kitchens.
The tiles on the right are hand cut straight from full sheets of stained glass. As you can see the consistency of size and shape is not as accurate then the machine made glass tile. However, hand cut tiles lend themselves better to many
art and craft projects, where they often actually look better than the mass produced straight edged glass tiles.