If you're buying your first piece of diamond jewellery, it's important that you have an understanding of what you're buying. In this guide I aim to simplify the criteria jewellers use to grade and value diamonds - Colour, Clarity, Cut and Carat (the 4C's) so you can make an informed decision when selecting your diamond. If you are looking for a more comprehensive explanation you can find this in my Diamond Buyer's Guide.
Confidently yours,
Alexander
Shape
Before we move on to the 4C's we must first deal with shape. Diamonds come in a variety of different shapes and this is the first thing you and/or your partner must decide upon. No one shape is better than another; it's just down to personal preference. Round diamonds are the most popular and trades above other shapes so are more expensive. Elongated shapes like marquise, oval and emerald suit longer fingers while princess cuts suit smaller hands. Pears and hearts are best used for pendants.
"If you're planning on a surprise engagement you will need to know this so use your guile to find out what she'd love."
All of the 4C's are as important as each other but as we can see the colour of a diamond with our naked eye special attention should be paid to this criteria. If you're going for a platinum or white gold item of jewellery you will want to go for a colourless diamond (D to F), for a yellow or rose gold piece a near colourless (G to H) diamond would look great. You should avoid diamonds of lower grades.
Note: Strongly coloured diamonds beyond Z, if desirable, are termed "fancies" and are extremely rare and valuable.
Fluorescence - Some diamonds fluoresce (glow blue) under UV light, in a nightclub for example, and some people seek these diamonds out. The downside to these diamonds is there is UV in sunlight so a near-colourless grade diamond with fluorescence will look whiter than it actually is and in some instances it will give the diamond a slight hazy or oily appearance. Diamonds with fluorescence are priced slightly lower than those without.
"My recommendation would be to go for an F or G colour diamond as these are high quality and offer excellent value when compared to a D or E."
The second C is Clarity which is the grade based on the imperfections (inclusions) found within a diamond. The terminology here is horrible but don't be put off diamonds with grades below flawless (no inclusions) as these inclusions are tiny and need high magnification to be seen if at all. They are also a sign that the diamond is natural and not synthetic or simulant. Some shapes, such as Emerald, require you choose a higher clarity grade as you can see more into that shape than others.
"I would recommend going for a clarity grade of VS, any inclusions within a diamond of this grade will only be seen through a microscope and will have no affect on brilliance."
Many gemmologists consider Cut the most important diamond characteristic and I am one of them. Even if a diamond has perfect colour and clarity, a diamond with a poor cut will have dulled appearance. The width and depth have the greatest effect on how light travels within the diamond, and how it exits in the form of sparkle (brilliance). Too Shallow: Light is lost out the bottom causing the diamond to lose brilliance. Too Deep: Light escapes out the sides causing the diamond to appear dark and dull. Diamond measurements are calculated and applied to a cut grading scale that makes it easy to understand how well each reflect light.
Polish and Symmetry - two important aspects of the cutting process. The polish grade describes the smoothness of the diamond's facets, and the symmetry grade refers to alignment of the facets. With poor polish, the surface of a facet can be dulled, and may create blurred or dulled sparkle. With poor symmetry, light can be misdirected as it enters and exits the diamond. The polish and symmetry grades are clearly listed in each diamond detail page and within the diamond grading report. For the most beautiful diamond, look for symmetry and polish grade of Excellent, Very Good or Good. Avoid diamonds with grades of Fair or Poor, as the alignment of their facets may misdirect light so severely that it affects the brilliance of the diamond.
"I believe in the importance of Cut so much that we only sell premium cut diamonds."
The final C is Carat, which is simply the weight of a diamond. This will be decided on by style and/or budget. If you've determined the shape, colour, clarity and cut grade you're going for, it's easy to determine the carat weight of the diamond that will fit within your budget. Keep in mind you're partners hands, the smaller the finger, the larger the diamond will appear and visa versa.
Note: Since larger diamonds are rarer than smaller diamonds, diamond values rise exponentially with carat weight.
"There are certain carat weights where big savings can be made. A 0.95ct can be 20% cheaper than a 1.00ct whilst looking almost identical."
Certification
Before purchasing a diamond, make sure it has a grading report from a reputable laboratory like the GIA or HRD. This is your guarantee of quality for that diamond; documenting the characteristics of a diamond including the 4Cs. GIA certificated diamonds are laser inscribed with the certificate number on the girdle for added peace of mind.
"Steer clear of EGL certificated diamonds, they are notoriously lenient with there grading!"