- Diamond Education
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- Jewellery Education
- Rings Education
- Metal Education
- Gemstone Education
- Which one of the 4 C’s of diamond grading is the most important?
- How do slight differences in the 4C’s affect a diamond’s value?
- On the diamond certificate, or diamond grading report, it is easy to read colour, clarity, carat weight and shape... But how do I tell if the diamond is well cut?
- Why do only round brilliant cut diamonds get a proportion grade?
- If the diamond has been certified is it important that I receive the original diamond certificate or diamond grading report?
- What is diamond plotting?
- Why is it important that my diamond certificate come from an independent diamond grading laboratory?
- How do I know that my diamond certificate or diamond grading report is from an independent laboratory?
- My retailer/merchant produces his own diamond report, is that sufficient?
- Why would I want my diamond certified by the DCLA?
- Who are the DCLA and what do they do?
- Will my diamond certificate or diamond grading report have a value on it?
- Do you keep a record of my diamond grading certificate?
- Can I bring my diamond jewellery to the laboratory for certification?
- What is diamond laser inscription?
- What sort of diamond laser technology does the DCLA use?
- I have a diamond ring with a total diamond carat weight of 1.5 carats in small diamonds. Are they worth the same as a single 1.5 carat diamond?
- Can you identify the latest diamond simulants, diamond treatments, and synthetic diamonds?
- My jeweller will not supply me with a certificate from an independent diamond grading laboratory, what should I do?
- What other security measures does the DCLA offer?
- What are “synthetic” diamonds?
- I want to get a diamond certified before I buy it, what should I do?
- I have a diamond “valuation,” is this not the same as a diamond certificate?
- If I buy a certified diamond, how do I know that the diamond in my ring is the one described on the diamond certificate or diamond grading report?
All of the 4 C's are equally important; however, many people consider diamond cut to be the most important diamond characteristic, because even if a diamond has perfect colour and clarity, a diamond with poor cut quality will have dulled brilliance and life.
The nature of diamonds is such that even a very SMALL variation in any of the 4 C’s will have a significant effect on value. To give you an idea of just how sensitive the value of a diamond is to each characteristic, here are some examples (assuming all other characteristics remain constant):
- Carat: a difference of 0.1 of a carat (or 0.02 grams) can affect the value of a diamond by as much as 70%.
- Colour: a diamond’s colour ranges from D to Z. However the “white” colour range is from D to I (D, E, F, G, H, I). The difference between each colour is very subtle; however a D colour diamond is around 200% more valuable than an I colour diamond. The difference between a D colour diamond and an E colour diamond(which is almost impossible to tell without a set of diamond master stones) can be as much as 40%.
- Clarity: even something as small as a pinpoint, which is only visible under a powerful microscope, can affect a diamond's value. Each pinpoint could reduce the value of a diamond by 40%.
- Cut: Round brilliant cut diamonds are more valuable per carat than other diamond shapes; and, obviously, well-made diamonds are worth more than a poorly made diamonds.
The value of the diamond represents between 80 and 95% of the value of a typical diamond ring. Therefore, it is easy to understand why the accuracy of the diamond grading report is so vital.
On the diamond certificate, or diamond grading report, you must look at the proportion grade,polish grade, and symmetry grade. These three grades together determine the overall make of a diamond, and are each respectively graded as either: Excellent, Very Good, Good, Mediumor Poor. The characteristics section of a Diamond Grading Report will tell you if there are any extra facets, naturals or holes in the diamond.
Only round brilliant cut diamonds will have a proportion grade as it is the only diamond shape with scientifically determined parameters. All other diamond shapes do not have a proportion grade as there are no set parameters, and therefore no standard, to compare different diamonds against.
It is very important to get the ORIGINAL diamond grading report. Summaries or photocopies are not sufficient, and will not protect you if there is a problem later.
Diamond plotting is the process of recording a diamond’s inclusions. At the DCLA, diamond plotting is done on a computer diagram, which is then stored in a database together with all the measurements and features of a diamond. This database is similar to a finger print database, as all diamonds have unique inclusions. The diamond’s plotting is shown on the diamond certificate, and is very important in the identification of a diamond.
If you were buying a house would you accept an inspection from the owner? Of course you wouldn’t, you would insist that the inspection be done by an expert with no financial interest in the transaction. This situation is the same when buying diamonds. Be careful of diamond reports produced in-house by diamond merchants or retailers, as the report may be inaccurate and overstate the actual grading of the diamond.
Ask the jeweller if the diamond certificate comes from an independent diamond laboratory or if it produced by a diamond merchant or retailer, then do your research. Make sure the certificate is issued by the DCLA or another highly respected diamond grading laboratory; DCLA is the only diamond grading laboratory worldwide to offer a full-replacement Diamond Grading Guarantee.top
No, diamond certificates or diamond grading reports produced by people who have a financial interest in a diamond are not independent, and therefore cannot be free of bias.
The DCLA is the only internationally affiliated and locally accredited diamond grading laboratory in Australia. Although there are other highly respected laboratories internationally, the DCLA is the only recognised diamond grading laboratory located in Australia, making it easier for Australians to deal with any problems or queries as they arise. In addition, DCLA is the only diamond certification laboratory to stand behind our work and offer a full-replacementDiamond Grading Guarantee.
The DCLA or Diamond Certification Laboratory of Australia is an independent diamond grading laboratory, and the only diamond grading laboratory in Australia that is internationally affiliated and recognised. Grading is done in accordance with IDC (International Diamond Council) rules.
Technology & Grading Process
DCLA Laboratory Team
A certificate is NOT a valuation and therefore does not indicate a dollar value. A diamond grading certificate is an in-depth description of a diamond’s characteristics, or 4 C's, while an appraisal or valuation is a written estimate of the approximate retail replacement value at a given point in time.top
A complete database is kept of all diamonds certified by the DCLA laboratory. Each diamond that is submitted to the laboratory for grading is issued with a unique, individual DCLA number; this number is used both to track the diamond as it progresses through the laboratory, and also as a reference number for identification once it leaves the laboratory.top
It is impossible to accurately grade diamonds while still in a setting, only estimates and approximations of the 4 C's are possible. The setting may hide inclusions, mask colour, and make accurate measurements and weighing impossible. You therefore need to have to have the diamonds removed from the setting before submitting them to the DCLA laboratory. Your jeweller will be able to do this for you, it is a quick and relatively inexpensive process.top
Laser inscription is the use of a very fine, precise laser beam to write a diamond certificate (diamond grading report) number or customised personal message on the girdle (outside perimeter) of a diamond. The diamond's laser inscription is totally invisible to the naked eye and can only be seen with a magnifying loupe. It does not change the colour or clarity grade of a diamond and is considered permanent as it can only be removed by a professional diamond cutter.
The DCLA uses the latest Photoscribe cold laser technology that allows excellent control during diamond laser inscription without damaging the diamond. The PhotoScribe cold laser is the only laser guaranteed not to damage or alter your diamond by penetrating beyond the surface.top
No, the value is not even close. A single 1.5 carat diamond with the same shape, cut, clarity and colour will be worth many times more then the 1.5 carats of small diamonds. This is mainly because large diamonds are rarer, and much more valuable.
The DCLA uses the latest equipment and technology to detect and conclusively identify treated diamonds, synthetic diamonds, and fake diamond simulants. All diamonds that are submitted for grading to the DCLA laboratory are screened for treatment and authenticity. Diamonds that require further testing are then examined and tested on advanced equipment to conclusively determine their authenticity.
Always use a jeweller this is willing to provide you with an independent diamond grading report or diamond certificate; without a diamond grading certificate from an independent diamond grading laboratory, you will not know the true quality of the diamond you purchase.top
You can have your certified diamond sealed in a DCLA Certicard® Seal which will provide a further safeguard against your stone being substituted. The seal has a number of security features including electrostatic security bars, pressure-sensitive transparent adhesive and Cryptoprint® text which becomes visible after opening the seal. It is therefore very difficult to tamper with the seal. This sealing will also protect your diamond against damage and dirt.
Synthetic diamonds or “man-made” diamonds are created in a laboratory using either HPHT (High Pressure High Temperature) or CVD (Chemical Vapour Deposition). The DCLA will only certify natural, untreated diamonds and therefore will not certify synthetic stones.
It is strongly advised that you purchase a diamond that has already been certified. Most reputable jewellers will sell diamonds that have already been certified by an independent, recognised laboratory. If you want the DCLA to certify a diamond we will gladly assist you, please give us a call for more information.
A diamond valuation is only done once the diamond has been set in the ring. Inclusions are hidden, colour is obscured, carat weight and measurements have to be estimated. This makes it impossible to determine the exact characteristics (4 C’s) of the diamond and consequently the “valuation” can be significantly different to the actual value. In fact most valuations have the following disclaimer: “Gemstones have not been removed from settings for accurate assessment, all grades and weights are approximate.” Often these insurance valuations are used as selling tools by jewellers; for example, when selling a diamond ring for $10 000 a jeweller may present a valuation for $15 000. The customer will think he is getting a very good deal, however the diamond ring had never ever been sold at that value.
There are a number of ways to verify that your diamond matches the diamond certificate it is purchased with. If you purchased a diamond that is laser inscribed, ask your jeweller to show you the laser inscription under magnification. This way, you will always be able to identify the diamond as your own.
DCLA also performs a verification service, for both DCLA certified diamonds and for diamonds certified by other internationally recognised laboratories. Bring or send your diamond, together with the diamond grading certificate, to the DCLA laboratory and the diamond will be conclusively matched against the certificate. DCLA can then cold laser inscribe the diamond with either the diamond grading certificate number, or with a personalised message.