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.

WEIGHT Calculation Formulas

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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.
Gemstones Carat Weight Calculator :	From the dimensions and shape, this page calculates the weight of a gemstone.

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.

USESEFUL LINKS

Laboratories & schools	Forums & Networks	Knowledge	Associations
www.gemnantes.fr (D.U.G. France)	www.gemologyonline.com/	www.fieldgemology.com/	www.crg-dug.fr/
www.gubelinlab.com (GUBELIN)	www.pricescope.com	www.mindat.org	www.gemstone.org (ICA)
www.aigslaboratory.com (A.I.G.S.)	www.geminterest.com	http://webmineral.com	www.agta.org (AGTA)
www.aigsthailand.com	http://polygon.net/	www.themelis.com/	www.dgemg.com/ (D-Gem-G)
www.gia.edu (GIA)	www.ganoksin.com	www.diamondse.info/	www.thaigemjewelry.or.th (TGJTA)
www.gemresearch.ch (GRS)		www.ruby-sapphire.com	Others
www.ssef.ch (SSEF)		www.swalagemtraders.com	http://gemme.la.rca.free.fr (Profile)
www.hrd.be (HRD)			Gemstones from a G emologist
www.igiworldwide.com (IGI)

Manja Thai Co., Ltd,
Manja Thai Co., Ltd.
50/31, Pan Road, Silom,
Bangrak, Bangkok 10500,
Thailand

Tel: +66 2635 0858
Fax: +66 2635 0859