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Gemstone Size vs. Weight Chart
Chatham Loose Stone Size Vs. Weight Chart

Now you can SAVE on Chatham loose stones from OurCustomRings.com. Refer to the chart below to determine the size and carat weight of stone you're interested in, then visit our Loose Stone Price Lists for more information. Please note, weights and sizes on this chart are estimates and can vary up to 10% either way. Loose stone quotes will be based on the weight of actual stones available.


Round (mm)

Diamond (ct.)

Emerald (ct.)

Ruby & Sapphire (ct.)

Alexandrite (ct.)
2.0 0.03 0.03 0.04 0.04
2.5 0.06 0.06 0.08 0.08
3.0 0.10 0.10 0.15 0.14
3.5 0.16 0.15 0.22 0.19
4.0 0.22 0.22 0.34 0.33
4.5 0.33 0.32 0.45 0.43
5.0 0.45 0.45 0.66 0.59
5.5 0.59 0.57 0.83 0.75
6.0 0.77 0.72 1.09 1.05
6.5 1.00 0.95 1.36 1.23
7.0 1.25 1.10 1.64 1.63
7.5 1.55 1.40 2.12 2.00
8.0 1.85 1.75 2.50 2.35
Oval (mm)
Diamond (ct.)
Emerald (ct.)
Ruby & Sapphire (ct.)
Alexandrite (ct.)
5x3 0.25 0.20 0.29 0.29
6x4 0.52 0.40 0.59 0.54
7x5 0.93 0.66 1.06 1.00
8x6 1.45 1.13 1.65 1.50
9x7 2.07 1.60 2.36 2.20
10x8 3.08 2.40 3.50 3.26
11x9 4.31 3.40 4.90 4.10
12x10 5.98 4.10 6.80 5.60
Trillion (mm)
Diamond (ct.)
Emerald (ct.)
Ruby & Sapphire (ct.)
Alexandrite (ct.)
3x3 0.11 0.09 0.12 0.12
4x4 0.27 0.22 0.32 0.29
5x5 0.52 0.43 0.65 0.55
6x6 0.91 0.68 0.95 0.87
7x7 1.43 1.10 1.60 1.43
8x8 1.77 1.55 2.00 1.89
9x9 3.04 2.25 3.42 3.00
Marquise (mm)
Diamond (ct.)
Emerald (ct.)
Ruby & Sapphire (ct.)
Alexandrite (ct.)
4x2 0.10 0.08 0.12 0.10
4.5x2.5 0.13 0.10 0.15 0.14
5x2.5 0.18 0.12 0.20 0.19
5x3 0.21 0.16 0.24 0.22
6x3 0.25 0.21 0.29 0.27
7x3.5 0.35 0.32 0.45 0.40
8x4 0.73 0.50 0.75 0.66
9x4.5 0.90 0.65 1.00 0.95
10x5 1.00 0.95 1.30 1.22
12x6 2.00 1.50 2.06 1.90
Octagon (mm)
Diamond (ct.)
Emerald (ct.)
Ruby & Sapphire (ct.)
Alexandrite (ct.)
5x3 0.25 0.25 0.35 0.33
6x4 0.50 0.48 0.70 0.65
7x5 1.00 0.87 1.30 1.20
8x6 1.76 1.35 2.00 1.86
9x7 2.70 2.16 3.10 2.86
10x8 3.90 3.00 4.40 4.18
11x9 5.50 4.00 6.18 6.00
12x10 7.40 5.10 8.30 7.90
Pear (mm)
Diamond (ct.)
Emerald (ct.)
Ruby & Sapphire (ct.)
Alexandrite (ct.)
5x3 0.22 0.20 0.25 0.23
6x4 0.46 0.35 0.53 0.49
7x5 0.76 0.58 0.87 0.80
8x5 0.90 0.76 1.02 0.95
9x6 1.42 1.05 1.62 1.45
10x7 2.14 1.59 2.43 2.27
11x9 3.72 3.00 4.18 3.95
Heart (mm)
Diamond (ct.)
Emerald (ct.)
Ruby & Sapphire (ct.)
Alexandrite (ct.)
3x3 0.11 0.09 0.15 0.14
4x4 0.27 0.22 0.32 0.31
5x5 0.52 0.43 0.65 0.57
6x6 0.91 0.68 1.00 0.90
7x7 1.43 1.10 1.60 1.52
8x8 1.77 1.55 2.00 2.05
9x9 3.04 2.25 3.42 3.10
Square (mm)
Diamond (ct.)
Emerald (ct.)
Ruby & Sapphire (ct.)
Alexandrite (ct.)
2x2 0.06 0.04 0.06 0.07
3x3 0.20 0.12 0.22 0.21
4x4 0.50 0.28 0.56 0.45
5x5 0.60 0.50 0.80 0.75
Baguette (mm)
Diamond (ct.)
Emerald (ct.)
Ruby & Sapphire (ct.)
Alexandrite (ct.)
4x2 0.11 0.10 0.14 0.12
5x3 0.27 0.20 0.32 0.28
6x4 0.60 0.47 0.66 0.63
7x5 1.05 0.90 1.20 1.11
  • Sizes specified are given in millimeter (mm) measurements.
  • All above weights are based on average depth and girdle thickness. Larger stones are subject to a wider weight range. Sizes & weights can vary up to 10% either way.


  • Click on your favorite Chatham-created gemstone below for more information, availability and loose stone prices:

    Available Chatham Gemstone Shapes

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