Standard Round Brilliant with Doubled Mains and Stars
GemCad Derived Rendering by Bob Keller Bob Keller

SRB Variation with Doubled Mains and Stars
SRB Variation with Doubled Mains and Stars
Angles for R.I. = 1.54 81 facets + 16 facets on girdle = 97
16-fold, mirror-image symmetry 96 index
L/W = 1.000 T/W = 0.618 T/L = 0.618 P/W = 0.442 C/W = 0.134 H/W = (P+C)/W+0.02 = 0.596 P/H = 0.742 C/H = 0.224
Vol./W^3 = 0.197 Brightness at 0 degrees tilt for R.I. = 1.54
COS = 64.4% ISO = 68.1%
Pavilion
pb 42.50 03-09-15-21-27-33-39-45-51-57-63-69-75-81-87-93 Cut to temporary center point
g 90.00 03-09-15-21-27-33-39-45-51-57-63-69-75-81-87-93 Cut to meet pb
pm 41.50 96-06-12-18-24-30-36-42-48-54-60-66-72-78-84-90 Cut to meet pb,g
Crown
cb 38.00 03-09-15-21-27-33-39-45-51-57-63-69-75-81-87-93 Cut to meet g - level girdle
cm 35.00 96-06-12-18-24-30-36-42-48-54-60-66-72-78-84-90 Cut to meet cb,g
s 27.00 03-09-15-21-27-33-39-45-51-57-63-69-75-81-87-93 Cut to meet cb,cm
t 0.00 Table Cut to meet s,cm
This variation of the SRB doubles the number of main and star facets in each course. Note that in this variation the symmetry increases from 8 fold to 16 fold - there are 16 each pavilion main, pavilion break, girdle, crown break, crown main and star facets. Increasing the number of facets increases the scintillation and is a way of scaling up the SRB to work with larger stones.


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