Natural stone tiles are distinct and unique

You should always view several pieces of the tile that is to be installed before the installation begins.  Since it has been created by nature, not only are no pieces exactly alike, those two pieces may not even be very similar.
The most common natural stone tiles include

Although both are stones and both are quarried from the earth, granite and marble (and marble’s relatives - limestone, onyx and travertine) are very different from each other. The greatest difference lies in the porosity, softness and durability of marble when compared to granite.
Do I have to buy the whole slab?