Derek
GemCad Ray Traces for RI = 1.76
Random Model Cosine Model ISO Model

Derek
Designed by Jim Perkins 07.04.01 jperkins@medina.ohio.net
A design for my nephew Derek's birthday ring - Happy Birthday Derek from Uncle Jim & Aunt Kim.
Angles for R.I. = 1.76 73 facets + 12 facets on girdle = 85
12-fold, mirror-image symmetry 96 index
L/W = 1.000 T/W = 0.567 T/L = 0.567 P/W = 0.442 C/W = 0.130 H/W = (P+C)/W+0.02 = 0.592 P/H = 0.747 C/H = 0.219
Vol./W^3 = 0.215 Brightness at 0 degrees tilt for RI = 1.76
COS = 88.7 ISO = 95.3
Pavilion
G 90.00 96-08-16-24-32-40-48-56-64-72-80-88 Cut girdle to establish stone size./TD>
A 42.00 96-08-16-24-32-40-48-56-64-72-80-88 Cut to tcp,level girdle.
B 40.51 04-12-20-28-36-44-52-60-68-76-84-92 PCP. Meet at girdle.
Crown
1 40.02 96-08-16-24-32-40-48-56-64-72-80-88 Set girdle width, level girdle.
2 33.23 04-12-20-28-36-44-52-60-68-76-84-92 Meet at girdle.
3 19.36 96-08-16-24-32-40-48-56-64-72-80-88 Meet at facet 1 & table.
4 14.00 04-12-20-28-36-44-52-60-68-76-84-92 Meet at facet 2.
T 0.00 Table Cut at 0 degrees, Meet at 3.


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