How to Value a Diamond

The single most important piece of advice all diamond buyers should know:

Never purchase a diamond based upon certificate grades alone.

Two diamonds with identical certificate grades are rarely equal in brilliance or value.

Example 1: The two diamonds below have identical GIA grades

Color: I         Clarity: VS1

Polish: Excellent         Symmetry: Excellent        Cut: Excellent

Why is diamond B approximately 20% more valuable than Diamond A?

1.] Diamond ‘B’ has better proportion evident in the larger ‘face size’.

Diameter Measurements: A = 7.41mm:   B = 7.58mm:

2.] Diamond ‘B’ is slightly whiter and more brilliant than ‘A’ even though both stones are graded GIA ‘I’ color.

Better and weaker examples of the same color grade is not unusual and must be taken into account when calculating correct value.

3.] The inclusions in diamond ‘A’ are located in the center (circled) whereas in diamond ‘B’ the inclusions are smaller and located towards the outside edge [circled bottom left].

Diamond ‘B’ is a more valuable example of a VS1 clarity grade.

At IQ every diamond is scrutinized for brilliance, proportion and correct value before being added to our inventory; less than 5% of all diamonds produced meet IQ’s demanding standards.

Example 2:

In rare instances other lab diamonds may be more valuable than a GIA stone with the same grades:

The diamonds below have identical grades from the GIA and EGL:

Color: I        Clarity: VS1

We know GIA grades are stricter than EGL and some other labs and therefore it would seem reasonable to assume that the GIA diamond would be more valuable.

When we compare the 2 stones ‘side by side’ however, a different reality unfolds.

The GIA stone is considerably smaller than the EGL; clearly this diamond has been cut to maximize weight rather than ‘face size’ and brilliance.

The ‘face size’ on this GIA diamond is appropriate for a 1.75 carat rather than a 2.25 carat. Weight has been left on the underside of this diamond making it heavier but not larger where it matters [face size].

Please note that the GIA has given this diamond ‘Excellent’ Polish and Symmetry grades? Difficult to understand…

In contrast the EGL diamond on the right is beautifully cut, brilliant and has a face size that relates correctly to the carat weight.

A GIA certificate does not guarantee a diamond is cut, graded or valued correctly.

Select a knowledgeable diamond company with an impeccable reputation.

We invite you to visit IQ Diamonds where clients receive a detailed education from GIA Educated Professionals, competitive prices and make their selection from an unparalleled collection of diamonds.

Compare GIA certified diamonds:

GIA certified diamonds with similar grades are rarely equal in value.

Example 1:

Based on GIA certificates alone, the 1.71 F/VS2 diamond on the left should be more valuable than the 1.70 G/SI1 on the right.

A side by side comparison however, reveals that the 1.70 G/Si1 Diamond on the right has a larger face, is more brilliant and is the more beautiful, valuable diamond.

GIA Diamond grades alone are not always reliable indicator for brilliance, cut or value.