Diamond Grading Techniques - Part 2

Today when searching for the perfect engagement ring, chances are you will be faced with the question of whether you should choose an engagement ring which has a certificated gemstone, or whether you should opt out. This diamond grading technique is a specialist practice and quite important. The question is; what does it mean to have a certificated gemstone and how does it become certified?

Carat

The carat weight of a diamond can (in rough terms) be equated to a size. A diamond that weighs 1.5 carat in a brilliant cut will usually measure approximately 6.5mm in diameter. Many jewellers are able to provide customers with a stencil gauge of diamond sizes and carat weights to give them a visual suggestion of what their diamond will look like if they choose a particular carat weight. Of course when comparing the dimensions of a diamond against its carat weight you must consider the proportions of the cut. If for example a diamond is cut a little deeper than normal then its dimensions will not equate with what a stencil gauge will suggest as the width of the stone will be less than expected, whereas a stone that is wider than normal but of the same carat weight will be shallower than is standard. This is by no means a precise tool, however it can still be very helpful when helping customers make a decision by getting a visualisation of its physical size. Of course this means if for example you have an old engagement ring or wedding ring with a gemstone set into it and are unsure of the carat weight a jeweller may be able to estimate its approximate carat weight by measuring its size. There are some tools with built in tables for this function also, as well as some more complex formulas to estimate the carat.

The carat weight of a stone should be measured before the gemstone is set, in order to give an accurate account of the piece of jewellery. When selling a piece of jewellery the customer should have a full account of the details of the piece with information such as the metal type, carat, gemstone type, cut etc. The carat weight should be measured using specialist gemstone scales.

Diamond Certificates

Of course today there is what is known as the 5th C. This is a diamond certificate or grading report which is an assessment of a diamond which details all of its qualities discussed above. It is performed by an independent laboratory or institution such as the IGI or EGL. It can provide a customer with assurance and confidence in their choice as well as providing them with a document for financial purposes. There has been growing interest in this additional option for customers and it is regularly available of diamonds of 0.50ct or higher weight.

At Harriet Kelsall Bespoke Jewellery we regularly source diamonds which are IGI and GIA certified. Today there is a growing awareness concerning the traceability and certification of gemstones, many high street jewellers are providing such services and it is important to ensure customers feel reassured about the product they are choosing to purchase. If you are considering choosing a diamond engagement ring without a certificate but are still interested in some of the details of the stone you could opt to have the gemstone send to be assessed by an independent body such as AnchorCert at the Birmingham Assay Office.