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Posted by Esslinger Staff

 

This is a guide on how to estimate the approximate weight of a gemstone based on its length to width ratio.

 

Round

Diamond: Average diameter² x depth x 0.0061 x weight correction٭

Color Stone: Average diameter² x depth x S.G. x 0.0018 x weight correction*

 

 

Oval

Diamond: Average diameter² x depth x 0.0062 x weight correction٭

Colored Stone: Average diameter² x depth x S.G. x 0.0020 x weight correction*
(use average length and width for diameter)

 

 

Pear

Diamond: Length x width x depth x adjustment factor x weight correction٭

Adjustment Factor

Length to width Ratio

Adjustment Factor

1.25:1.00 0.00615

1.50:1.00

0.00600

1.66:1.00

0.00590

2.00:1.00

1.00575

Colored Stone: Length x width x depth x S.G. x 0.0018 x weight correction*

 

 

Marquise

Diamond: Length x width x depth x adjustment factor x weight correction٭

Adjustment Factor

Length to width Ratio

Adjustment Factor

1.25:1.00 0.00565

2.00:1.00

0.00580

2.50:1.00

0.00585

3.00:1.00

1.00595

 

 

Emerald Cut

Diamond: Length x width x depth x adjustment factor x weight correction*

Adjustment Factor

Length to width Ratio

Adjustment Factor

1.00:1.00 0.0080

1.50:1.00

0.0092

2.00:1.00

0.0100

2.50:1.00

0.0106

 

 

Heart

Diamond: Length x width x depth x 0.0059 x weight correction٭

Colored Stone: Length x width x depth x S.G. x 0.0021 x weight correction*

 

 

Triangle

Diamond: Length x width x depth x 0.0057 x weight correction٭

Colored Stone: Length x width x depth x S.G. x 0.0018 x weight correction*

 


 

٭ Weight Correction

All Cuts: Add between 3% and 8% depending on thickness of the girdle. A high or lumpy crown may require a correction of up to 10%.

Oval, Pear, Marquise, Heart: Add up to 10% for wide wings or high shoulders.

Step Cuts: Add up to 18% for pavilion bulge.

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