There are many different diamond grading reports available.
In my opinion, the most reliable diamond grading reports are those issued
There are numerous sources of information you can use to establish
the reputation of the company you wish to buy from, including
the local Chamber of Commerce, Better Business Bureau, personal
references, etc. Also note that companies who are members of
the Better Business Bureau are bound by a dispute resolution
agreement and risk a good rating if they don't resolve differences
with customers or honor return policies, etc.
Dimonz has a complete, unconditional 90 day money-back guarantee
policy on all diamonds sold from our inventory.*
On this website, I've included what I consider to be sufficient
information to make a good decision on purchasing a round diamond.
You should familiarize yourself with all the information on
color, cut, clarity and carat weight, and how to read GIA
diamond grading reports (please see 4 C's and GIA Certificates.
It is impossible to tell whether fancy
shape diamonds (i.e., princess, cushion, oval, emerald, Asscher, radiant, pear shape, marquise,
heart shaped, et al) are well cut
from the G.I.A. report. Fancy shape diamonds
that are poorly shaped may sell at a discount of up to 50% (or more) than well-made diamonds of the same color, clarity and carat weight.
In my opinion, the majority of fancy shaped diamonds (90% or more) have
been cut improperly to save weight from the rough (since diamonds
are sold by carat weight, saving weight increases profit). Also, since we don't have a recognized standard to evaluate the cut of fancy shaped diamonds like we do for round diamonds (e.g., Tolkowsky's American Ideal Cut) it is extremely difficult, if not impossible, for someone not engaged in the diamond trade to determine whether or not these stones are properly cut.
example, many marquise, pear shapes, and ovals
have pronounced "bow-ties" or dark, extinguished areas that
reduce the brilliance of the stones (usually caused by the stone
being cut too deep or too shallow). Princess cuts tend to be cut too deep, look smaller than they should for their carat weight, have
thin crowns and do not play well with light. Emerald cut diamonds are frequently too squarish or have "bulged pavilions"
(extra weight added by distorting the shape of the bottom
part of the stone).
Some pear shapes look more like a shield than a "tear drop"
(a phenomenon known as high shoulders with a flat head). Many
fancy shapes have improper length-to-width ratios, making them
either too fat or too thin to be aesthetically pleasing. Oval and marquise shaped diamonds may be cut too
wide or fat to retain weight from the rough or they may have "flat
wings" (i.e., the four arcs that form the outline of the stone
are flattened rather than rounded), creating an undesirable
shape. Also, GIA reports for fancy shaped diamonds do not contain the crown height percentage (ie., the height of the crown of the diamond expressed as a percentage of the width of the stone) which is essential in determining whether the stone will play well with light. These are just a few of the problems you could encounter
when buying a fancy shape.
Below are proportional diagrams taken from GIA reports for a round brilliant cut stone (on the left) and a fancy shape diamond (on the right). Not only do GIA reports not provide an overall cut grade for fancy shape diamonds (as they do for round brilliant cut diamonds), as you see below there is very little information contained in the proportional diagrams for fancy shape diamonds as compared to round brilliants.
This is one
area where you need the help of an expert who has your interests in mind- not a sales clerk
at a jewelry store or someone who may use his or her knowledge against you. Please call me (Bill Bailey) to discuss
how to evaluate the cut of different shapes and/or find out
what I have in inventory (phone # 703-237-6856). You may also
let me know if you want me to conduct a search for your stone.
Remember to consider only G.I.A. certified diamonds. Don't only consider color, clarity and carat
weight- also consider cut. Make sure that round diamonds
you consider purchasing meet the cut criteria described on this web-site
(see GIA Certificates and 4 C's). Remember, diamonds with an inferior cut can
sell for up to 50% less than diamonds that are very finely cut, particularly fancy shaped diamonds.
As noted in Rapaport Diamond Report, a wholesale pricing guide used world-wide, Poorly made (fancy shaped diamonds) often trade at large discounts while well-made stones may be hard to locate and bring premium prices (September 2015 edition).