Polished concrete is a form of honing the surface much like Granite and Marble.
The process is a tedious one, involving large grinders with vacuum assist that grind the floor in many successive steps. The finished result leaves a high gloss floor that does not have a coating or finish on the surface. A wide variety of Hardeners are available to densify your finished surface. Polished floors can also be dyed in a rainbow of colors. A well maintained polished floor can add light refraction and long term wear.