pavilion cutting

Note: This is a six-part edited version of Trevor Hannam’s Faceting Made Easy, a general introduction to faceting and a guide for learning to cut a standard brilliant gem. Part 4 includes Chapters 9 and 10. These chapters cover pavilion cutting and polishing. The International Gem Society thanks Mr. Hannam for permission to post his work.

Pavilion Cutting

Set the new angle on the protractor to 42°. This is the appropriate pavilion main angle for a topaz gem. Reset the index to 96 if you have not done so.

Place the coarse lap on the master lap. Don’t forget to clean everything prior.

Now, you’re ready to cut what’s known as the “Eight Complex.” These are the first eight facets you’ll cut. I recommend cutting them opposite to one another. This will reduce the chances of progressive errors, which you must avoid.

The Eight Mains Complex

Using your coarse adjuster, lower the head assembly so that the gemstone just touches the lap. Then, lock it into position. Next, turn on the machine and water, at a moderate rate, and lower the quill by the height adjuster.

When cutting or polishing, always use a sweeping motion across…