| GemCad Ray Traces for RI = 1.70 | ||
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| Random Model | Cosine Model | ISO Model |
| K12 Oval 1.1
Designed by Fred Van Sant 1997 Rendered by Bob Keller |
|
| Angles for R.I. = 1.70+ | 45 facets + 12 facets on girdle = 57 |
| 2-fold, mirror-image symmetry | 96 index |
| L/W = 1.100 Table Area= 32.5% T/W = 0.5867 C/W = 0.1455 | P/W = 0.4618 H/W = 0.6273 g2/W = .27482 |
| VF = .23347 GVF = .004116 | Brightness at 0 degrees tilt for RI = 1.70
COS = 82.2 ISO = 91.3 |
| Pavilion | |||
|---|---|---|---|
| 1 | 41.00 | 20-28-68-76 | Cut to equal depth, make permanent center point |
| 2 | 41.86 | 12-36-60-84 | Meet permanent center point |
| 3 | 41.00 | 04-44-52-92 | Meet permanent center point |
| g1 | 90.00 | 20-28-68-76 | Match 1, set size |
| 4 | 50.00 | 11-37-59-85 | Meet g1.1.2 |
| 5 | 63.37 | 04-44-52-92 | Meet 2.3.4 |
| g2 | 90.00 | 11-37-59-85 | Meet g1.1.2.4 |
| g3 | 90.00 | 04-44-52-92 | Meet g2.4.5 |
| Crown | |||
| 1 | 43.44 | 04-44-52-92 | Match g3, establish upper girdle line |
| 2 | 45.92 | 11-37-59-85 | Meet g3.1.g2 |
| 3 | 45.11 | 20-28-68-76 | Meet g2.2.g1 |
| 4 | 34.00 | 07-41-55-89 | Meet g3.1.2.g2 |
| 5 | 34.00 | 24-72 | Meet g1.3.3.g1 |
| 6 | 24.00 | 07-41-55-89 | 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 = .5867 |
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.
