What kind of shell mosaic need grout when decorating?

This captivating mother of pearl tile in oyster white is artfully arranged in a square pattern. The pearl shell glass will add a durability and lasting exquisiteness to your kitchen, or fireplace installation. The mesh backing not only simplifies installation, it also allows the tiles to be separated which adds to their design flexibility.
Some people may cannot recognize what kind of shell mosaics need to use grout or not. Now I can give you an answer. 
Shell mosaics include all regular mosaics can be divide in two kinds----mosaics with joint and mosaics without joint. Mosaics with joint should installed with grout because mosaics are always have mesh on back, if we don’t use grout, the mesh will be exposed and that will be ugly. 
Mosaics without joint can be install without grout, simply speaking, there is no space to have grout. So, if you don’t like grout, you can decorate your house with seamless mosaics.
Now , I give you two pictures to compare.

This shell mosaic has 2 mm joint, so you should buy grout when decorating house in case of the mesh exposed.

This mosaic is seamless and there is no need to buy grout when decorating.