It is essential to seal a floor as this will protect it from stains and marks. The best sealers today are made from silicone and are translucent. There will be a slight smell when they are first applied but this will disperse quickly. A matt stone sealer will not change the colour or appearance of a stone floor. A polished stone sealer will add a slight sheen to the surface of most stone tiles.
It is possible to darken most rustic / more open stones with a wax such as Lilothin Classic wax. These products will darken the overall tone of the tile. If applied by a tiler with a buffing machine they will also add a slight sheen to the surface. This can work very well with a rustic material such as terracotta – however it is always best to try a sample patch first
Polished or high density limestones and marbles will not absorb a wax. It Is possible to raise the sheen on these floors with products such as Lilothin Multiseal however it is not possible to darken polished or high density hard stones