GemCad Derived Rendering by Bob Keller

SRB Variation with Highlight Breaks | |
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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 | |||
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g | 90.00 | 02-06-10-14-18-22-26-30-34-38-42-46- 50-54-58-62-66-70-74-78-82-86-90-94 | 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. |