Stone contains natural crystals. These crystals reflect light to provide a shine on the surface. When the crystals are dull, crushed, or broken, they cannot reflect light evenly. For example, when the lens of a flashlight breaks, it cannot reflect the light that is being emitted from the bulb.
Polished stone floors become dull when heavy foot traffic along with sediment erodes the crystals. Normal footwear does not cause the main damage, sediment and grit do. The sediment and grit that lies on the stone surface is the main enemy of the stones crystals. The damage to the crystals occur when the pressure from the shoe forces the sediment to abrade or fracture the crystals.
The only safe way to restore and sharpen the crystals is to polish them with diamond abrasives or polishing powders. The life span of crystals can be extended by administering a thorough dust mopping program with proper cleaning tools and products.