Standard Round Brilliant with Highlight Breaks
GemCad Derived Rendering by Bob Keller
SRB Variation with Highlight Breaks Angles for R.I. = 1.54 73 facets + 24 facets on girdle = 97 8-fold, mirror-image symmetry 96 index L/W = 1.000 T/W = 0.508 T/L = 0.508 P/W = 0.450 C/W = 0.154 H/W = (P+C)/W+0.02 = 0.624 P/H = 0.721 C/H = 0.246 Vol./W^3 = 0.205 Brightness at 0 degrees tilt for R.I. = 1.54
COS = 66.5% ISO = 70.8%
Pavilion g 90.00 02-06-10-14-18-22-26-30-34-38-42-46-
Cut to equal depth, establish size pm 42.00 96-12-24-36-48-60-72-84 Cut to equal depth, establish girdle pb 43.00 02-10-14-22-26-34-38-46-50-58-62-70-74-82-86-94 Meet g,pm ph 43.53 06-18-30-42-54-66-78-90 Meet g,pb,pm Crown cm 32.00 96-12-24-36-48-60-72-84 Cut to equal depth - establish upper girdle line cb 34.50 02-10-14-22-26-34-38-46-50-58-62-70-74-82-86-94 Cut to meet g,cm ch 36.22 06-18-30-42-54-66-78-90 Cut to meet g,cb s 18.00 06-18-30-42-54-66-78-90 Cut to meet ch,cb,cm t 00.00 table Cut to meet s,cm This variation of the SRB splits the break facets with a third facet instead of a single dividing ridge. Note there are 24 equal girdle segments in this variation instead of the usual 16 with an 8-fold symmetry SRB. Adding more facets by "fanning out" the breaks increases the scintillation and is one way of adapting or scaling the SRB for use with larger stones.
The SRB with Highlight Breaks Design File is available for GemCad users.