Polishing involves grinding surplus diamond away to leave the facets. Most of the work done, and weight removed from a rough diamond is done in this way. Bruting involves rubbing the rough diamond against another by rotating it, to make the circular shape of the finished stone. This is performed before the grinding operation. Polish can be used to mean the actual quality of the polish which has been achieved on each of the facets.
Proportion also has multiple meanings.
The most important proportion and the easiest to ascertain is the ratio between the depth of the stone and its diameter. The ratio between the height of the crown and that of the pavilion is also important. Why Proportion Matters Well proportioned stones reflect more light, and therefore often appear whiter and brighter than poorly proportioned stones. 2 or 3 colour grades better than it actually is. Similarly, diamonds in perfect proportion may also look better than other diamonds of higher clarity, but which are not as well cut.