Last updated on December 26, 2022
Diamond is an expensive purchase. Whether you buy a loose diamond as an investment or create a unique custom setting, you should pay special attention to some guidelines to get your money’s worth and choose the best stone you can afford. Here is the list of essential rules for buying loose diamonds.
Rule No. 1 – Ask For a Certificate
A diamond certificate, also known as a grading report, is a document referring to the information on the quality characteristics of a particular diamond where each of the features is graded on a standard scale.
This scientific examination is to prove that the quality of the diamond has been evaluated by an independent third-party gemological authority such as the Gemological Institute of America (GIA), International Gemological Institute (IGI), European Gemological Laboratory (EGL) and others.
Without this document, any claims about the diamond’s colour, clarity, cut, polish, symmetry, and other features remain unverified, meaning you make a purchase based on the seller’s opinion. That is why you should always ask for a certificate/grading report to make sure you get what you are paying for.
Rule No. 2 – Look for a Laser Inscription

Laser inscription is related to diamond certification. It is a unique combination of letters and numbers engraved on a diamond girdle that serves as an ID to identify a particular stone among others. The laser inscription is done by the lab at which the diamond is certified, and it should match the ID written on the grading report. That is how you know that the certificate describes the stone you are looking at.
The inscription is crucial as it allows you to recognize your diamond among other similar-looking stones. For example, if someone attempts to replace your diamond with another stone, you can always check its inscription to make sure you have the right diamond.
Always remember to tell your jeweller about the inscription so the person doing the repairs will be careful not to damage it by accident. When you get the stone back, check the inscription to make sure you have the same stone.
It is important to mention that not all diamonds are laser inscribed. Some manufacturers prefer not to pay for inscription services. In such a case, you can identify your stone by its plot, which is a diagram included in a certificate. A diamond plot maps all the flaws in a diamond and allows identifying it among others as the number and location of inclusions are unique to each stone.
Rule No. 3 – Compare Diamond Prices
It is always useful to compare diamond prices quoted by different sellers. It may turn out that though a salesperson claims you are getting a super discount in their shop, the “discounted” price is the price everyone else sells at. However, it is crucial to make sure you are not comparing apples and oranges, meaning diamond characteristics should be the same or at least very close.
In addition to the 4Cs (colour, clarity, cut quality and carat weight), there are lots of factors such as fluorescence, polish, symmetry, girdle thickness and culet size that go into diamond pricing. All these characteristics significantly affect the final diamond price.
Remember that prices per carat go up the bigger a diamond gets. The increase is because bigger diamonds are rarer compared to small ones. Moreover, prices jump sharply at popular carat weights such as 0.50, 0.75, 1.00, 1.25, 1.50, 2.00 and so on. Such carats are in greater demand and therefore cost more. To save some money, you may opt for stones slightly below these popular carat weights – the diamond will look the same size to the naked eye, but it will cost less.
Rule No. 4 – Inspect the Diamond Under Magnification

It is always a good idea to inspect a loose diamond with a loupe or jeweller’s microscope before you buy it.
Check if there are any potentially harmful inclusions to the diamond structure. For example, cracks and lines can be really dangerous. If they are big enough, they can weaken the stone’s internal structure. Avoid diamonds with long lines inside them, especially the ones with lines that reach the surface of the stone. Such inclusions make the stone even more prone to damage, meaning the diamond will crack if hit hard enough.
Look at the surface of the diamond and make sure it is not chipped or damaged. Pay special attention when looking along the stone’s edges since those parts are more vulnerable to chipping.
Look at the diamond’s natural flaws and compare it to the other stones you are considering. You should be comfortable with the level of clarity you are getting. As a general rule, the clarity grade should be high enough, so there are no visible flaws to the naked eye.
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