K12 Oval 1.55
GemCad Ray Traces for RI = 1.70
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.

  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, 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.


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