Each mother of pearl tile is naturally 2mm. The major difference in mother of pearl tiles is the quality of the shell. Another very important difference is the variety of different thicknesses of the tile. You can find mother of pearl tiles which are 2mm thick or 8mm thick. It’s logical to assume that because the thicker tiles are also more expensive, that they will be better quality and last longer. But in fact, that’s not actually the case. What a thicker mother of pearl tile has is a ceramic backing. The actual mother of pearl content on that tile is the same as the 2mm version.