A Round Cushion
| GemCad Ray Traces for RI = 1.76 | ||
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| Random Model | Cosine Model | ISO Model |
| A Round Cushion Designed by Charles W. Covill covill@email.msn.com | |
| Angles for R.I. = 1.76 | 49 facets + 16 facets on girdle = 65 |
| 4-fold, mirror-image symmetry | 96 index |
| L/W = 1.000 T/W = 0.557 T/L = 0.557 P/W = 0.469 C/W = 0.140 | H/W = (P+C)/W+0.02 = 0.629 P/H = 0.746 C/H = 0.222 |
| Vol./W^3 = 0.230 | Brightness at 0 degrees tilt for RI = 1.64 COS = 58.4 ISO = 70.6 |
| Pavilion | |||
|---|---|---|---|
| 1 | 45.00 | 02-22-26-46-50-70-74-94 | Cut to meet at false culet. |
| 2 | 43.83 | 06-18-30-42-54-66-78-90 | Cut to meet with 1 at false culet. |
| g2 | 90.00 | 06-18-30-42-54-66-78-90 | Complete level girdle line. |
| 3 | 41.00 | 08-16-32-40-56-64-80-88 | Meet 2 at girdle,make new culet. |
| Crown | |||
| g1 | 90.00 | 02-22-26-46-50-70-74-94 | Determine size of stone. |
| 1 | 32.21 | 96-24-48-72 | Establish girdle thickness. |
| 2 | 35.00 | 02-22-26-46-50-70-74-94 | Meet 1 at girdle,continue level girdle |
| 3 | 35.00 | 06-18-30-42-54-66-78-90 | Meet 1 & 2,complete level girdle. |
| 4 | 29.00 | 12-36-60-84 | Meet 1,2 & 3. Also meet 3 at girdle. |
| t | 0.00 | Table | |
| With g1 cut 8 equal sides, Determine size of stone. Cut pavilion facets 1 & 2 to meet at false culet. Cut g2 to complete level girdle line. Cut pavilion facet 3 to meet girdle and form new culet. |
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Diagram PDF
GemCad File