GemCad Derived Rendering by Bob Keller

SRB Variation with Highlight Breaks and Stars | |
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Angles for R.I. = 1.54 | 89 facets + 24 facets on girdle = 113 |

8-fold, mirror-image symmetry | 96 index |

L/W = 1.000 T/W = 0.592 T/L = 0.592 P/W = 0.450 C/W = 0.128 | H/W = (P+C)/W+0.02 = 0.598 P/H = 0.753 C/H = 0.213 |

Vol./W^3 = 0.199 | Brightness at 0 degrees tilt for R.I. = 1.54
COS = 69.9% ISO = 73.6% |

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 | 35.50 | 02-10-14-22-26-34-38-46-50-58-62-70-74-82-86-94 | Cut to meet g,cm |

ch | 38.09 | 06-18-30-42-54-66-78-90 | Cut to meet g,cb |

s | 24.00 | 02-10-14-22-26-34-38-46-50-58-62-70-74-82-86-94 | Cut to meet ch,cb,cm |

sh | 20.60 | 06-18-30-42-54-66-78-90 | Cut to meet s,ch,cb,cm |

t | 00.00 | table | Cut to meet s,cm |

This variation 'highlights' the stars of the SRB in addition to splitting 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 and stars increases the scintillation and is one way of adapting or scaling the SRB for use with larger stones. |