K12 Oval 1.67
GemCad Ray Traces for RI = 1.70
Random Model Cosine Model ISO Model
K12 Oval 1.67
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 = 1.67 Table Area= 28.3% T/W = 0.5607 C/W = 0.1901 P/W = 0.6717 H/W = 0.8819 g2/W = .38277
VF = .556091 GVF = .006358 Brightness at 0 degrees tilt for RI = 1.70
COS = 62.0 ISO = 76.4
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 - set size
4 46.40 18-30-66-78 Meet g1.1.1.g1
5 64.38 08-40-56-88 Meet 2.1.4
6 72.64 02-46-50-94 Meet 3.2.5
g2 90.00 08-40-56-88 Meet 5.4.g1
g3 90.00 02-46-50-94 Meet 6.5.g2
Crown
1 48.30 02-46-50-94 Match g3, establish upper girdle line
2 39.61 08-40-56-88 Meet g2.g3.1
3 42.16 18-30-66-78 Meet g1.g2.2
4 34.00 06-42-54-90 Meet 1.g3.g2.2
5 34.00 24-72 Meet 3.2.4, g1.3.3.g1
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.

  1. 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.
  2. Breakpoint Method:
    a. Cut pavilion set 1 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.


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