In days where almost all tiles were normal ceramic - glazed on a terracotta type mix, the edges were not the same colour as the tile glaze, so edger or trim as it's often called, was and still is used.
This would be plastic in recent decades and there is still a range of colours you can choose from.
Most are rounded edge, but there's a range of rectangular edged trims for a more contemporary look.
However, there are other options:
Plastic trim
Different colours
Some of the many colours available in plastic
Metal trim
Aluminium, polished chrome or brushed
Butt fit overlap
Only certain tiles or natural stone have a glazed edge or the colour and texture running through
Some ceramic tiles have a coloured edge allowing for butt overlap corners
Can work well with many porcelains. It's your choice depending on your tile and they all differ.
Works particularly well with natural stone
Glass tiles
Mitred
Higher cost, time and dust!, plus special cutters, but for some designs and tiles, this effect is sometimes requetsed.
Pencil mosaic
Mitered grey porcelain with hand-made cast concrete ledges
Mitered vertical corner with butt overlap on the top
Mitred ceramic glazed metros
Mixed gallery
