K12 Oval 1.1
GemCad Ray Traces for RI = 1.70
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.

  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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