Dishwashing detergent might be one of the worst cleaner to use. Not because it'll wear the stone, but because it produces too many suds and will leave a dulling film. Find a cleaner that is intended for stone, it'll also have the right ph so no damage.
Marble from Italy
DIRECT Containers MARBLE from ITALY - PERLATO di SICILIA - PERLATINO - BOTTICINO - AVORIO - LIMESTONE -- others - Slabs - Tiles - Custom sizes and textures.