Faceting Made Easy, Part 6: Gemstone Design Cuts

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 6 includes the gemstone design cuts section as well as the bibliography. The International Gem Society thanks Mr. Hannam for permission to post his work.

The Emerald Cut

The emerald cut is basically designed for medium to dark colored stones or those with a low refractive index (RI). Although the depth of this gemstone design will enhance lighter colored stones, it does nothing for brilliance or scintillation.

Angles shown are for quartz. The best gemstone proportion ratio is 1.5 to 1.

Pavilion

1. 90° 96-48-24-72
2. 63° 96-48-24-72
3. 43° 96-48-24-72
4. 53° 96-48-24-72
5. 53° 12-36-60-84
6. 63° 12-36-60-84
7. 90° 12-36-60-84

Cut the midway and corner facets with a 1,200 lap. Polish in reverse order.

Crown

1. 55° Girdle, Indices 96-48-24-72-12-36-60-84. (Cut these facets to establish a girdle height 5% that of finished gem height).
2. 42° Mains, Indices 96-48-24-72-12-36-60-84
3. 27° Stars, Indices 96-48-24-72-12-36-60-84

Polish in reverse order.

Table

Table (4), use 45° angle dop. Set it up parallel with the lap surface. Then, set angle to 90°. Cut and polish.

Notes on

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Trevor Hannam

Born in Wudinna, South Australia, Trevor G. Hannam moved to Cairns, Queensland in 1966. Introduced to faceting by Kay and Jimmy Gadd, he learned to facet with the help of Bob Johnson. After completing a diploma in Earth Science, he continued to study the art of gemology through Kye Jewellers. Currently retired, as a member of the Cairns Mineral and Lapidary Club, he taught the art of silver smithing, gemology techniques, and faceting.

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