The Diamond Standard - Cut [Part 3]

Customers often ask what is the ideal thickness of the girdle?

Depends on whether the stone is round or fancy cut. Well made round stones should have a thickness of 0.5% to 5% of total depth of stone.

The culet is graded from “none” to “small”. Does “small” mean the culet has been cut to ideal proportions?

“Small” indicates size of culet only and does not affect proportions of stone until the size reaches “medium” and larger.

Why is the emerald cut less brilliant?

This is because faceting in brilliant cuts maximizes the balance between life (brilliance) and fire (dispersion), faceting in emerald cut diamonds does not.

Why are “fancy cut” diamonds not cut to a standard formula like round diamonds?

There is more flexibility in cutting of fancy shapes. Fancy cuts have recommended ratios of length to width.

Assuming they are the same quality which has the higher value, a round brilliant or an emerald cut diamond?

The present market demand is higher for rounds (brilliants) than emerald cuts; but this can always depending on market conditions.

What kind of cut gives the best reflection?

The brilliant cut maximizes the balance between life (brilliance) and fire (dispersion); because cut is a question of taste and all cuts are beautiful in their own way. Brilliant cut has a 58-facet arrangement that radiates from the centre of the stone towards the girdle, and has triangular facets.

Why can there be different table sizes in two diamonds of the same caratage?

Diamonds with the same carat weight can vary enormously in their style of cutting. Cut depends on the nature of the rough, the polisher, and the different proportions of cut that are sought in various markets, since not all markets have the same preference.

Will the cut affect a diamond’s value?

It is important to understand the difference between the cut, that is the shape of the diamond, which is entirely dependent on your taste and the skill of the diamond cutter in producing the finished.

Do heart shaped, emerald cut, and pear shaped diamonds have a standard number of facets?

No, the number of facets can vary for heart shapes and pear shapes. Emeralds have the same number of facets.

Which kind of diamond cut is the most valuable/expensive?

This is dependent on what the market demands dictate.

Is it correct that the more facets a diamond has, the better it is?

No, although, some registered cuts claim to provide grater brilliance and scintillation, however, as is the case with all diamonds. Beauty is in the eyes of the beholder.

Are there accepted international proportions for the heart shape cut diamond and which is better, one that appears fat or one that appears thin?

The ideal proportion for a heart shape is 1:1 length to width ratio.

How can one tell if a diamond has been badly cut?

It is worth pointing out that a diamond that has been badly cut will not have the same fire, brilliance, scintillation and light as that in a diamond that has been well cut to maximize these qualities.