| GemCad Ray Traces for RI = 1.70 | ||
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| Random Model | Cosine Model | ISO Model |
| K12 Oval 1.55
Designed by Fred Van Sant 1997 Rendered by Bob Keller |
|
| Angles for R.I. = 1.70+ | 49 facets + 12 facets on girdle = 61 |
| 2-fold, mirror-image symmetry | 96 index |
| L/W = 1.55 Table Area = 30.5% T/W = .5607 C/W = .1749 | P/W = .6507 H/W = .8456 g2/W = .325259 |
| VF = .472339 GVF = .005745 | Brightness at 0 degrees tilt for RI = 1.70
COS = 66.7 ISO = 79.4 |
| Pavilion | |||
|---|---|---|---|
| 1 | 41.00 | 20,28,68,76 | Cut to equal depth - make PCP (culet) |
| 2 | 41.00 | 12,36,60,84 | Meet culet |
| 3 | 41.00 | 4,44,52,92 | Meet culet |
| g1 | 90.00 | 18-30-66-78 | Cut to equal depth, establish size |
| 4 | 47.00 | 18-30-66-78 | Meet g1.1.1.g1 |
| 5 | 63.70 | 09-39-57-87 | Meet 2.1.4 |
| 6 | 74.37 | 03-45-51-93 | Meet 3.2.5 |
| g2 | 90.00 | 09-39-57-87 | Meet 5.4.g1 |
| g3 | 90.00 | 03-45-51-93 | Meet 6.5.g2 |
| Crown | |||
| 1 | 45.72 | 03-45-51-93 | Match g3, establish upper girdle line |
| 2 | 42.21 | 09-39-57-87 | 1.g3.g2 |
| 3 | 43.98 | 18-30-66-78 | Meet 2.g2.g1 |
| 4 | 34.00 | 06-42-54-90 | Meet 1.g3.g2.2 |
| 5 | 34.00 | 24-72 | Meet 4.2.3, 3.g1.g1.3 |
| 6 | 24.00 | 06-42-54-90 | Meet 4.1.1.4, 4.2.3.5 |
| 7 | 24.00 | 24-72 | Meet 6.4.2.3.5 |
| T | 0.00 | Table | Table Width / Width = .5607 |
There are two ways to make the K12 Oval shape.
- At 90° cut the side and end pairs to make L/W. Then cut the other four girdles at 90° to achieve g2/W by measurement.
- Breakpoint Method:
a. Cut pavilion set 1, 2 & 3 to PCP.
b. Cut four facets at 90°, end indices, to size stone.
c. Chain-cut break facets, starting as shown, to meetpoints as you go.
d. Chain-cut girdles at 90°, starting next to the ends, to make a level girdle line.
