The cutter generally polishes the star facets last on the brilliant cut diamonds. It is almost like playing “connect the dots” because, if the stone has been properly cut these facets will fall right into place. If the cutter takes his time, he can polish all of the stars the same distance into the table, creating a perfect (or close to perfect) octagon shape. Stars are very important because they are so very viewable on the top of the diamond. If the stars are different shapes, or the table star edges aren’t symmetrical, it affects the symmetry of the finished diamond and the stone is unattractive. Often the cutter will smash the stars into one another, shrinking the table unnecessarily and blunting what should be sharp, clean, triangular points. Cutting off-grain (not perpendicular) creates frayed facet edges around the table, which are In the second illustration, you can see the obvious easily recognized under 10x degrees inconsistency in the final shape of the girdle due to over- digging of the halves. In the lower illustration, the halves were pasted on which shows very little digging from the girdle. This will have a very negative affect on the brilliance of the diamond.
The Diamond Star Facet by Definition | Star Facet Importance
Like the upper and lower girdle facets, the star facets allow a further multitude of light path directions, creating more brilliance.