Diamond Grading, Grades
When purchasing certified diamonds it is important to understand the diamond grading criteria used by the laboratories performing the certification.
Diamond grading covers numerous aspects of each individual diamond’s qualities, but there are four grades which are critical to understand: cut, clarity, color, and carat weight. There are additional ratings and measurements noted on a diamond certificate, but they generally fall under the diamond’s grade in one of the Four Cs. For example, measurements listed such as “depth” and “table” are part of the description of the diamond’s cut.
You can learn more about how diamonds are graded by reading the articles listed below.
Cut is probably the most important quality factor, and most challenging, of the four Cs to understand. The brilliance of a diamond depends heavily on its cut. More info…
Most diamonds contain some inner flaws, or inclusions, that occur during the formation process. The visibility, number and size of these inclusions determine what is called the clarity of a diamond. Diamonds that are clear create more brilliance, and thus are more highly prized, and priced. .
Colourless diamonds are the most desirable since they allow the most refraction of light (sparkle). Off white diamonds absorb light, inhibiting brilliance.
A carat is the unit of weight by which a diamond is measured. Because large diamonds are found less commonly than small diamonds, the price of a diamond rises quickly as its size increases.
The larger a diamond the more expensive it is and as we rise up the scale of size the prices rise dramatically. There are key price points 0.25,0.5,0.75,1.0,1.25,1.5,18.104.22.168,22.214.171.124,3.5,4.0,4.5,5.0.The reality is that a 0.97 carat can be a lot cheaper than a 1 carat. People often like to be able to have an exact number a 1 carat weight is a key point. In the business we often refer to an 80 pointer which means 0.8 of a carat or we may refer to a stone as being a one fifty which means that it is one and a half carats.
The Fifth C: Certificates
The diamond certificate, which is sometimes called a grading report, is a complete evaluation of your diamond that has been performed by a qualified professional with the help of special gemological instruments. Each stone bears its own recognizable, individual characteristics, which is listed on the certificate. The most recognised certificate in the business is the GIA certificate. The IGI and HRD are also widely recognised and highly thought of.
There are various other certificates around but the bottom line is if you buy one of the above it will be exactly what it says on the certificate!!The EGL certificate has not got the greatest reputation and should be treated with great caution. We will not accept anything we read on an EGL cert unless we verify it independently with our gemologist. Having said all that EGL certed stones are cheaper and the odd bargain does come through.
There are also some uncarted stones which doesn’t mean they are bad –some manufacturers simply want to turn the stone around quickly and are doing so in high volumes and hence the stone is uncerted. This is often the case in smaller stones of less than one carat.
The reality in larger more valuable stones is that they should be certed and there is no reason that they should be offered uncerted.