Significance
The rough cut is the first step where the gemstone's individual qualities become apparent. Removing the rock or other ore surrounding the pure gem, the rough cut maintains as much of the volume of the original gem as possible while enabling a skilled cutter to see inside the gem.
Function
An expert will thoroughly evaluate the rough cut for dimensions and impurities to determine further action with the stone. Major inclusions might cause the cutter to split the "rough" into several roughs, which will then be evaluated as individual smaller pieces.
Effects
From the rough cut, the cutter will use several factors to determine the shape, angles and size of the final cut. The most obvious of these is maximizing final volume, or carat. The depth and brilliance that will result from the interaction of dimension and cut is also an important factor, especially for smaller or more artistic cutters.