Weight Conversion Tables

The weights given are for sapphires cut to ideal proportions. Although generally that is not the case, as mixed cuts (step cuts on the pavillion and brilliant cuts on the crown) as well as angles of convenience are often used, this chart gives a reasonable indication. The point is not to take these figures too literally, but to use them as a starting point for estimating weights.

 

 


 
Round (mm)
Sapphire (carats)
  2.0 0.04
  2.5 0.08
  3.0 0.15
  3.5 0.22
  4.0 0.34
  4.5 0.45
  5.0 0.66
  5.5 0.83
  6.0 1.09
  6.5 1.36
  7.0 1.64
  7.5 2.12
  8.0 2.50
Oval (mm)
Sapphire (carats)
  5x3 0.29
  6x4 0.59
  7x5 1.06
  8x6 1.65
  9x7 2.36
  10x8 3.50
  11x9 4.90
  12x10 6.80
Octagon (mm)
Sapphire (carats)
  5x3 0.35
  6x4 0.70
  7x5 1.30
  8x6 2.00
  9x7 3.10
  10x8 4.40
  11x9 6.18
  12x10 8.30
Square (mm)
Sapphire (carats)
  2x2 0.06
  3x3 0.22
  4x4 0.56
  5x5 0.80
Marquise
Sapphire (carats)
  4x2 0.12
  4.5x2.5 0.15
  5x2.5 0.20
  5x3 0.24
  6x3 0.29
  7x3.5 0.45
  8x4 0.75
  9x4.5 1.00
  10x5 1.30
  12x6 2.06

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