Cleaving is the process of striking a stone to split it along its grain. If a rough stone has noticeable flaws and/or inclusions that would make it impossible to turn into a single gemstone, it is cleaved. The propensity of crystalline materials to split along specific planes is known as cleavage. A diamond can cleave in four different directions parallel to each of the four octahedron crystal faces because of its atomic structure. Since a mistake by the "cleaver" could break the stone, cleaving is an essential stage.

A phosphor bronze narrow disk is used as a stone-cutting saw. The cutting agent, diamond dust, is continuously picked up or "recharged" by the saw blade as it turns. A 1 carat raw diamond may take the saw blade many hours to cut through.

The procedure of "bruting" involves placing two diamonds on opposing spinning axles and allowing them to grind against one another until each diamond is round. Another name for this is girdling. Only round brilliant diamonds require the bruting technique; fancy cut stones require a different kind of preparation.

The procedure of cutting the diamond's facets and doing final polishing is called polishing. The blocking, faceting, and polishing procedures are all part of the process.
The polishing process consists of two stages, the first of which is blocking. Because it creates the fundamental symmetry of the stone, the blocking stage sets the benchmark for the diamond's brilliance. The diamond's initial 17 or 18 facets are produced by blocking. The polishing procedure ends here when working with a tiny diamond. Bigger diamonds proceed to brillianteering, the second stage.

In the last step, the diamond is extensively cleaned in acids and examined to determine whether it satisfies the manufacturer's quality standards. At this stage, the jeweler or diamond wholesaler has the option of selling the stone uncertified or having it examined by a trustworthy independent laboratory to obtain a diamond grading report.