Quick guide

The purpose of this guide is to assist in the general public in picking out a great diamond. The target audience is intended for those aiming to purchase an engagement ring.

But why should you buy a loose diamond and not a diamond already in a ring setting at a local jeweller? One reason is because when you go to a store and see the diamonds in a setting, there's no way to know if there is anything wrong with the bottom of the diamond without taking it out and appraising it. Since a diamond is a commodity (like silver and gold), you would want to get the best possible diamond for the best price, not by brand name.


If you don't want to be flooded with all this information, you can go straight to section G for a much condensed version. But if you want to learn, let's start.



The 4 C's and so much more (13 important factors)


Remember that all of the following information, you will be able to find on the diamond certificate.  Make sure you go through EVERY one of these criteria before buying a diamond.  Note that more high-end retailers such as Tiffany’s, Birks, etc, may or may not show you the certificate.


A.        Very very important factors (Factors GREATLY affecting the price of a diamond)


1. Cut - ensures that a given stone has maximum brilliance and sparkle.

ID - Ideal

EX or X - Excellent

VG – Very Good

G - Good


2. Colour - Rated from colourless to yellow.

D, E, F – colourless

G, H, I, J - near colourless

K and on – bad


3. Clarity- How big the inclusions are in a diamond, i.e. flaws

FL – flawless

IF - internally flawless

VVS1, VVS2 - very very small inclusions

VS1, VS2 - very small inclusions

SI1, SI2 - small inclusions

I1, I2 - inclusions


Fran’s comment: The clarity must be at least SI1 since it is still not visible to the naked eye. VS2 or higher preferred


4. Carat – how much it weighs


B.        Very important factors (Factors MODERATELY affecting the price of a diamond)


5. Polish - Refers to the external finish of the facets. An "good" polish grade reflects the quality of the work the diamond cutter has put into the stone. Symmetry: Graded according to how precisely the facets are aligned (i.e., the top of the facet should mirror the bottom of the facet). A facet that does not have symmetrical sides will negatively affect how light reflects from the stone.

ID - Ideal

EX or X - Excellent

VG – Very Good

G - Good


6. Symmetry

ID - Ideal

EX or X - Excellent

VG – Very Good

G - Good


7. Flourescence - A variety of luminescence. The property of changing one kind of radiation to another.

NO - None

NEG - Negligable

FtB - Faint Blue

Md B - Medium Blue

Str B - Strong Blue



C.        Important factors


8. Girdle - The girdle is the narrow belt around the stone, which divides the top portion of the diamond (crown) from the bottom portion of the diamond (pavilion). Girdle is usually expressed as a range, indicating that it may vary from one part of the stone to another. If a girdle has small, flat, polished surfaces on it, it is referred to as "faceted".


9. Culet - The small facet that is polished parallel to the table at the pavilion, sometimes left pointed.



Very small




Very Large

Extreme large


10. Depth % - Depth refers to the height of a diamond from the culet to the table. The depth percentage listed on the certification indicates the height of the diamond relative to the width measurement (height value, width value). A diamond which is too shallow or too deep will disperse light through the sides or the bottom instead of the top facet. 60% is optimal.


11. Table % - The largest flat surface on the top (crown) of the diamond. The table percentage refers to how much of the total width is occupied by the table. A table that is either too large or too small will negatively affect how Light reflects up from the surface of the stone. 57% is optimal.


12. Crown angle – 34 deg is optimal


13. Pavilion angle - 40.5 deg is optimal


D.        Certification


AGS – American Gem Society:  The Best!  AGS has the highest/tightest rating system for diamonds. AGS000 is a diamond that has Ideal cut, polish, and symmetry, also colourless and flawless or internally flawless.  Only 1/10th of 1% of diamonds fit the AGS Triple Zero criteria.


GIA – Gemological Institute of America: Almost the best!





E.        Hearts & Arrows diamond


Hearts & Arrows diamonds are the best and rarest and brightest diamonds.  Here are the criteria it has to have:


Cut – Must be certified by AGS or GIA as an Ideal cut.

Polish – Must be certified by AGS as Ideal and GIA as Excellent.

Symmetry – Must be certified by AGS as Ideal and GIA as Excellent.

Depth % - Must be between 58.7% and 62.3%

Table % - Must be between 53% and 58 %


If all these criteria’s are met, when you look at the diamond under the loupe or Hearts and Arrow viewer, you will see these patterns:


Who are we?

The Geohavens name is an assurance of timeless beauty, distinct quality and uncompromising value. The Company spares no effort in sourcing from the farthest markets and the deepest mines in order to unearth the most attractive gems.

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