Diamond Weight Estimation Formulas

Rounds = …………………..Diameter x Diameter x Depth x .0061

Ovals = ……………………..Length x width x Depth x .0062

Princess Cuts = …………..Length x width x depth x .0083

Heart Cuts = ……………….Length x width x depth x .0059

Triangle Cut = ……………Length x width x depth x .0057


Emerald Cut = ……………Length x width x depth x factor:
Factor…..Length to width ratio
.0080      1.00 : 1
.0092       1.50 : 1
.0100        2.00 : 1
.0106        2.50 : 1


Marquise Cut = ………….Length x width x depth x factor:
Factor…………Length to width ratio
.00565      1.50 : 1
.00580      2.00 : 1
.00585       2.50 : 1
.00595       3.00 : 1


Pear Cut = ………………….Length x width x depth x factor:
Factor……..Length to width ratio
.00615       1.25 : 1
.00600      1.50 : 1
.00590       1.66 : 1
.00575        2.00 : 1

Colored Gemstone Weight Estimation Formulas

Round Faceted = …………….Diameter x diameter x depth x SG x .0018

Oval Faceted = ……………….Diameter x diameter x depth x SG x .0020

Emerald Faceted = …………..Length x width x depth x SG x .0025

Rectangle Faceted = …………Length x width x depth x SG x .0026

Square Faceted = …………….Length x width x depth x SG x .0025

Marquise Faceted = …………Length x width x depth x SG x .0017

Pear Faceted = ………………..Length x width x depth x SG x .0018

Heart Faceted = ……………….Length x width x depth x SG x .0018

Table of Specific Gravities for Popular Gemstones

Zircon: ………………4.32 – 4.70
Diamond: …………..3.52
Conch Pearl: ………..2.85
Almandite Garnet: .4.05
Peridot: ………………3.34
Turquoise: …………..2.76
Ruby: ………………….4.00
Jadeite: ……………….3.34
Lapis Lazuli: ………..2.75
Sapphire: …………….4.00
Zoisite (tanzanite) ..3.35
Beryl Group: ………..2.72
Malachite: ……………3.95
Diopside: ……………..3.29
Pearl: …………………..2.70
Rhodolite Garnet: …3.84
Spodumene: …………3.18
Quartz: ………………..2.66
Pyrope Garnet: ……..3.78
Andalusite: …………..3.17
Coral: …………………..2.65
Chrysoberyl: …………3.73
Tourmaline: ………….3.06
Iolite: ……………………2.61
Spinel: …………………..3.60
Nephrite: ……………….2.95
Opal: ……………………..2.15.