K12 Oval 1.15
GemCad Ray Traces for RI = 1.70
Random Model Cosine Model ISO Model
K12 Oval 1.15
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 = 1.15 Table Area= 31.4% T/W = 0.5867 C/W = 0.1571 P/W = 0.4828 H/W = 0.6600 g2/W = .276533
VF = .265905 GVF = .00433 Brightness at 0 degrees tilt for RI = 1.70
COS = 81.8 ISO = 90.2
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 19-29-67-77 Cut to equal depth, set size
4 54.00 19-29-67-77 Meet g1.1.1.g1
5 62.56 11-37-59-85 Meet 2.1.4
6 69.51 03-45-51-93 Meet 3.2.5
g2 90.00 11-37-59-85 Meet 5.4.g1
g3 90.00 03-45-51-93 Meet 6.5.g2
Crown
1 45.84 03-45-51-93 Match g3, establish upper girdle line
2 45.69 11-37-59-85 Meet g2.g3.1
3 47.28 19-29-67-77 Meet g1.g2.2
4 34.00 07-41-55-89 Meet g3.1.2.g2
5 34.00 24-72 Meet 3.2.4, 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.


Index of Gem Designs

Perfect Transfer Index

Table of Contents


© Bob's Rock Shop Bob Keller