Weight estimation formula for mounted princess

Jewelry Discussion
1

Dear All,

Has anyone developed a weight estimation formula for mounted
princess cut diamonds?

Jon Michael Fuja

2

Software – Gemology Tools has a weight estimator for diamonds and
colored stones in its program. You have to be able to measure the
size of the stone.

john

3

Jon, Regarding your question: Has anyone developed a weight
estimation formula for mounted princess cut diamonds?

Yes, Charles Carmona of Guild Labs has not only developed formulas
for all sort of diamond shapes and cuts but also for those of
colored gems. Get his book: “The Complete Handbook for Gemstone
Weight Estimation.” You can find it at:

Renee Newman

4 
Has anyone developed a weight estimation formula for mounted
princess cut diamonds?

Methods for estimation gemstone weight had been known for many
years.

The general formula is is length X width X depth X shape modifier X
SG x correction factor.

Shape modifier for princess is 0.29 Correction factor is where
experience and observation skills come into play.

Formula works fine as long as it is ideal cut. For ideal cut
correction factor is 1.

Any deviations from correct proportions has to be accounted in
correction factor.

For shallow crowns and/or shallow pavilions correction factor is
less than 1.

Pavilion bulges, thick girdles, extra large culets, and etc. -
correction factor is greater than 1 and in some extreme cases can
approach 1.7 or even greater.

Leonid Surpin