Until the 1940s there was no universal way to judge diamond quality, and each company or country would have their own system. The founder of a GIA (Geological Institute of America) Robert Shipley developed the 4C’s of diamonds as a way to help students recall the many factors involved in judging diamond quality. Since then, jewellers worldwide have switched to using his method as the agreed-upon standard. This means that jewellers can explain the quality of a diamond in a universal way, and their customers can now understand the factors associated with that quality and thus the price.
The 4C’s of diamonds can be broken down in order of importance:
- Cut Grade
- Colour Grade
- Clarity Grade
- Carat Weight
The carat weight of a diamond has been placed last on the list simply because the other three factors can impact the diamond quality enough to negate its importance. Two diamonds with the same carat weight can have a very different quality and price depending on the cut, colour and clarity.
The cut of a diamond should be considered the highest priority in the 4C’s of diamonds, as even a pristine high carat diamond with no inclusions or colour can appear dull if it hasn’t been cut properly. A diamond that has colour, or a lesser clarity can, to the eye, appear just as beautiful because of its ability to reflect light properly.
There are 5 levels of cut grade:
- Very Good
The way a diamond is cut will impact the appearance in three different ways:
The way light is reflected from both internally (the facet angles) and externally (the surface) of the diamond.
When light enters the diamond it is scattered throughout the facets. This is visually shown as flashes of the colours of the visible spectrum.
When a light source is moved, scintillation is shown through flashes of light and dark - also known as sparkle!
Cut grade should not be confused with shape (oval, round, heart, pear, marquise), but should instead be an indication of how well the facets interact with light. Diamond cut grade is the hardest of the 4C’s to properly analyze.
Cutting a diamond properly has much to do with choosing the correct proportions. A well-proportioned diamond has been cut so its facets angle light back up from the bottom and sides so it reflects out of the crown (top face). If a diamond doesn’t have the ideal proportions it will lack the same amount of brilliance, fire or scintillation. Choosing a diamond in the Fair to Good cut grade range can allow a budget conscience shopper to find a larger diamond.
Unless referring to Fancy grade diamonds, diamond colour is actually the lack of colour. Diamonds range from brilliant white to pale yellow and are graded on a scale of increasing saturation from D (colourless) to Z (subtle yellow).
Fancy diamonds come in pink, yellow, blue, orange, green, and red and are graded based on their saturation. A smaller diamond may be priced higher than a larger diamond based on the intensity.
When viewing diamonds, it is very common to see tiny imperfections inside the stone. These are called inclusions and form during the diamond’s crystallization or during the mining process. The fewer the inclusions, the higher the value of the stone. The diamond clarity scale reflects the visibility of the inclusion.
There are six main categories, with 11 total grades:
Under 10x magnification, a flawless diamond will show no faults. A very small percentage (~2%) of the diamonds in the world can be considered flawless. It is common for retail stores to carry VVS as their highest diamond clarity grade.
Internally Flawless (IF)
This grade of diamond has no internal flaws and only has surface blemishes that can be removed by gentle polish with little loss of carat weight.
Very Very Small Inclusions (VVS)
This diamond clarity grade has internal faults that are very, very difficult to observe, or has finishing faults
Very Small Inclusions (VS)
This grade has either several larger inclusions, or several tiny inclusions that are difficult to find.
Small Inclusions (SI)
These diamonds have inclusions that are easily found by qualified persons.
Inclusions in this grade of diamond can be observed by a professional with the naked eye and can substantially lower it’s value.
Diamond weight was originally measured using carob seeds as a point of reference, which lead to the current word carat.
The final 4C of diamonds is Carat weight, usually shown as ct., measures the total weight of the diamond. There are 200 milligrams per carat, the same weight as a paper clip, which is then subdivided further by 100 points in order to allow precision measurements.
Carat weight is the most visible of the 4C’s, but as discussed above, not necessarily the most important - unless its in reference to your budget. The larger a diamond is the rarer it is, and thus will hold a higher value.
This introduction to the world of diamond production is the first in our series of diamond education. Understanding where your beautiful jewelry came from and what elements make it up is part of our mission at Harling’s Jewellers in Vancouver.