Gemstone Size to Weight

This page contains conversion formulas for various gemstone cuts to find the weight from the size of the gemstone in millimeters and vice versa. This should be usefull when estimating how much an order should cost you. S.G. stands for specific gravity.

Quadrature
Jewelry Manufacturing
Thailand.
( French - English )

Precious Metals Calculator.	Evaluates the current on-line price of all carat golds, silver, platinum, and palladium. Uses the current on-line price for a variety of currencies.
Wax Calculator for Castings.	You have a wax, but need to know the weight of the cast gold piece. And its value. Or you have a brass or silver model. This page evaluates the current on-line price of all carat golds, silver, platinum, and palladium. Uses the current on-line price for a variety of currencies.
Weight Units Converter.	Convert weights between grams, carats, pennyweights, and ounces
Diamonds Size to weight Table	Gives an approximate guide to the relative size in millimetres, and weight of modern round brilliant cut and fancy cut diamonds of ideal proportions.

Carat Weight Calculator

Hereunder the standard formula

Round faceted stones:
Diameter squared x depth x S.G. x .0018 = ct

Oval faceted stones:
Length x width x depth x S.G. x .0020 = ct

Emerald cut faceted stones:
Length x width x depth x S.G. x .0025 = ct

Rectangular faceted stones:
Length x width x depth x S.G. x .0026 = ct

Square cut faceted stones:
Length x width x depth x S.G. x .0023 = ct

Marquise cut stones, (navette):
Length x width x depth x S.G. x .0016 = ct

Pear cut stones:
Length x width x depth x S.G. x .0018 = ct

Square cushions:
Diameter squared x depth x S.G. x .0018 = ct

Rectangular Cushions:
Diameter squared x depth x S.G. x .0022 = ct

Square step cut stones:
Diameter squared x depth x S.G. x .0023 = ct

Rectangular step cut stones:
Length x width x depth x S.G. x .0025 = ct

Cabochon cut stones:
Length x width x depth x S.G. x .0027 = ct

Average corner meas & belly meas for cushions,
L&W for rectangles, etc..
For more acurate calculation please use the online calculator.

AGA Homepage About Us Links