How to Cut Diamonds by Hand

A rough, uncut diamond.

Even if it is the size of an apple, an uncut diamond lacks the wow factor that a perfectly cut smaller rock possesses. In order to reveal the hidden fire and magnificent brilliance of a diamond in the rough, its flaws must be cut away.

Things You'll Need

• Uncut diamond Smaller diamond for scoring Heavy steel blade Padded claws or plaster of Paris Thin disc of phosphor bronze Diamond dust Oil

Instructions

1. Cleave the rough diamond along the weak planes that are constructed by the quartz structure. The only way to become an expert at spotting where the weak planes are is through practice or observation of a professional. See the links below for video tutorials. Mark the position of the cut on the stone in ink.

2. Score along the line cut into the diamond marked by ink with a smaller diamond. Strike sharply against the groove with a heavy steel blade. The diamond will either shatter into pieces or cleave cleanly in two, depending on if you have marked the point for cutting correctly.

3. Clamp the resulting of the cleaving between padded claws that is known as a "dop." Lower the diamond onto a very thin disc of phosphor bronze for spinning. This disc will be rotating between 4,000 and 6,000 times per minute.

4. Coat the edge of the disc with a mixture of diamond dust and oil to facilitate the slow cutting through the diamond. A one carat diamond can be expected to take around six hours to cut. Shape the diamond by rubbing it against another diamond. This process is known as bruting.

5. Cut and polish the facets to bring out the brilliance of the diamond. Mount in the dop again and coat with more diamond dust and oil. Plug the finished diamond into boiling sulphuric acid to cleanse of dirt and grease.

Tips & Warnings

• If you don't have a dop, you can also mount the diamond sawing in plaster of Paris.

• Since sulphuric acid is incredibly dangerous, the final process of cleansing should only be done by a professional.

Resources

• Diamond cutting tutorial
• The Diamante diamond cutting machine
• The Art of Diamond Cutting