GemCad Derived Rendering by Bob Keller

SRB Variation with Spiked Mains | |
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Angles for R.I. = 1.54 | 57 facets + 16 facets on girdle = 73 |

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

L/W = 1.000 T/W = 0.559 T/L = 0.559 P/W = 0.458 C/W = 0.160 | H/W = (P+C)/W+0.02 = 0.638 P/H = 0.718 C/H = 0.251 |

Vol./W^3 = 0.209 | Brightness at 0 degrees tilt for R.I. = 1.54
COS = 47.0% ISO = 50.9% |

Pavilion | |||
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pb | 43.50 | 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 | 42.50 | 96-12-24-36-48-60-72-84 | Cut to meet pb,g |

Crown | |||

cb | 42.00 | 03-09-15-21-27-33-39-45-51-57-63-69-75-81-87-93 | Cut to meet g - level girdle |

cm | 36.00 | 96-12-24-36-48-60-72-84 | Cut to meet cb,g |

s | 22.00 | 06-18-30-42-54-66-78-90 | Cut to meet cm,cb |

t | 0.00 | Table | Cut to meet s,cm |

This simple variation of the SRB reduces the difference in elevation angle between the pavilion break and main facets from 2° in the classic version to 1° in the spiked mains variation, which produces deeper breaks and a tighter, more acutely shaped starburst pattern at the culet. |