People often ask why some diamond certificates are more descriptive than others. For example, some laboratories offer more information on an individual stone. However (like anything), this is not always necessary. However, if you are about to spend a lot of money on something, the more information provided, the better. So let’s take a closer look at why some diamonds have more information.
Why some diamond certificates are more descriptive
Generally speaking, diamonds smaller than 0.20ct will not be individually certified, but sold within the diamond trade in large parcels. However, Night Sky stones between carat weight 0.20 – 0.29ct are usually certified with reputable South African laboratories. Companies like IDL and EGL as the value of stones in this category does not warrant certification expenses.
Stones with a carat weight from 0.30ct and upwards ARE certified with the GIA laboratory and EGL (South Africa).
What is the difference between the GIA and EGL? Both laboratories are equally strict in their grading systems and uphold high standards in their accuracy and consistency. The difference is that the GIA is global with multiple diamond grading facilities worldwide.
Apart from the 4 Cs, there are some other criteria you might want to consider before making your purchase. These additional attributes can be found and described on all GIA diamond certificates and three-fold EGL (South Africa) diamond certificates.
1. Cut grade
Specific to round brilliant shape diamonds. The cut refers to the overall make of the stone regarding its proportions. Usually determined by the weight and shape of the stone while still in its rough state. The cut of a round brilliant stone needs to conform to specific parameters to maximise the stone’s potential brilliance and life.
Night Sky would recommend that the cut be either excellent or very good. It will guarantee the most desirable scintillation that a diamond should have.
It is important to note that the cut grade reference only applies to round brilliant diamonds. There are no absolute rules on how to cut and shape the stones when it comes to any other shape.
A particular artistic license is acceptable depending on the shape of the stone in the rough and preference in shape. For example, cushion cut diamonds: you can have both square cushion-cut diamonds and rectangular cushion cut diamonds. The facets on both models are the same, but the silhouette is slightly elongated on the rectangular version.
The same applies to radiant cut diamonds and emerald-cut diamonds. Whereas pear shape diamonds and heart shape diamonds may differ slightly from one another in their silhouette. It again comes down to the buyer’s personal preference.
2. Symmetry grade
You can apply it to any Diamond Shape. For example, a laboratory judges the proportion symmetry of a diamond by the accuracy of how the stone is cut. To be made up of exactly similar parts facing each other around an axis. A simple example of this would be while cutting/polishing a Heart Shape Diamond. If you drew an imaginary line down the center of the heart to its tip, do the lobes of either side of the heart match in diameter and overall shape?
To go even further, take into account the facet symmetry. It is an evaluation of length, placement, presence, or absence of the facets themselves.
3. Polish grade
It can apply to any diamond Shape. The polish refers to the care and finesse with which the diamond cutter places the stone’s facets. The graders do the polish grade of the stone in the final stages before being sent to a laboratory.
Diamonds are notoriously complex. Care needs to be taken in applying pressure that the cutter exhorts on the stone against the cutting wheel. Even the direction the facet runs against the cutting wheel makes a difference. Polish features affect only the surface of the stone and are not considered inclusions.
Typical polish features that can occur can be anything from tiny scratches, transparent polish lines, and burnt facets. These are quickly removed but unattended could affect the luster of a stone. Night Sky takes care to eliminate all such polish features to produce good to excellent polish grades on our stones.
4. Fluorescence
It does not refer to the make of the stone but a natural characteristic present in varying degrees and intensity. Under UV, a diamond may fluoresce in a range of colours and its intensity could range from strong to faint.
Fluorescence in diamonds is largely misunderstood. On VERY rare occasions, fluorescence can make the appearance of a diamond look slightly milky. However, this an exception. Usually, fluorescence in diamonds make them appear whiter than they actually are and. For this reason, it can benefit the stone’s appearance.
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