Now for some new terminology. Gem cutting is done using a metal disc that spins at very high speeds and is impregnated with tiny particles of diamond. The stone is brought into contact with the disc, and a facet is born. This disc is called a "lap." The picture above shows the magnified surface of a lap. Notice the diamonds gleaming on the surface.

	In the process of preforming, the gem is often hand-held and is raked across the surface of the lap to grind the rough into the desired preform, as shown in the image to the left.
	Here is our completed preform, very roughly approximating our design in overall shape and having a flat spot ground where the table will be.