When buying a diamond, it's important to do your research before you commit to your purchase. To make your experience enjoyable and hassle free, we offer free consultations to assist you in the decision making process. At Stephens Jewellers we ensure that you receive exceptional service and value. At the same time we strongly encourage you to do your own research and gain an understanding of what it is you are looking for in a diamond. To assist you we have prepared the below Diamond Buying Guide.

How much should you spend on a diamond?

That is very much up to you. Some people consider one or two months’ salary a good guide for an engagement ring. The important thing to remember is that unlike a wedding dress, a diamond engagement ring is worn everyday of your life so you would be wise to choose something that will continue to give pleasure year after year, because a diamond really is forever.

How do you determine the quality of a diamond?

To determine a diamond’s quality and worth you begin with the 4 C’s: Clarity, Cut, Colour and Carat weight. These are the traditional units of measure when looking at this precious stone, however, you must add one more imperative ‘C’ to the list and that is Certification.


This relates to the marks of non-crystallised carbon called ‘inclusions’ found within the diamond. The inclusions vary in standards on the spectrum ranging from FL (flawless), SI1 () to I3. It is exceedingly rare for a diamond to be flawless, known as FL and is the highest level on the spectrum. SI1 is in the middle of the spectrum and it is recommended when buying a diamond, you should not purchase lower than this standard. I3 is the lowest as it includes the mot inclusions and is least clear.


The cut of a stone is not relating to the shape, but refers to the way the cutter has formed it to best ensure that light bounces within the stone and back out through the top. If it has a defective cut (too long or too short) the light refracts on the inside and falls out down the bottom. This decreases the brightness and lustre of the stone. A well cut stone is neither exceedingly long nor shallow, it is luminous and will always dazzle even when dirty.The grading system varies from Ideal Cut to Good and lastly, Poor Cut. With round diamonds, it is suggested to never purchase below ‘Very Good’ and ‘Good’ in all other shapes. Again, the better cut stone the more it will cost.


Ensure that you receive a certificate when buying diamonds. There are a few highly reputable grading houses around the world and they include GIA, AGS and DCLA. Never accept the certificate of the retailer, even if they are GIA certified. Only accept certificates from the above mentioned graders as they maintain high standards and ensure that the quality of the stone is exactly what you have paid for. Other labs are pressured to lower their standards, therefore you will be paying for a lower quality stone for a higher price.

Hearts & Arrows

However, if this is not enough, you can go beyond the highest level of quality and purchase a ‘hearts and arrows’ diamond. This is the perfect diamond. It is the perfect cut which enhances the way the light bounces in and out of the top of the diamond. When looking through the telescope from the top you will see arrowheads lining up with the shaft and when looking down on the bottom you will find perfectly shaped hearts. There are many who boast of having the perfectly cut diamond, however though there may be the appearance of hearts and arrows, they can be misleading.

Tips to identify the perfect hearts and arrows:

  • There must be 8 hearts and 8 arrows.
  • All hearts and arrows must be the same in intensity. Meaning one cannot be brighter than the other.
  • All hearts and arrows must be of the same colour.
  • There should be a gap between the heart and V shape under it.
  • The V shape under the heart's must all look exactly the same.
  • Arrow heads and hearts should be the same shape as each other.
  • The arrow heads should line up to the shafts.
  • The hearts should not be pointed.
  • Be aware that GIA’s highest standard of diamond does not automatically constitute your stone being hearts and arrows. It may state on the card that it is hearts and arrows, however only certificates from HRD Antwerp Labs will provide the guarantee that your diamond is in fact true hearts and arrows.At minimum it is suggested that you adhere to the 4 C’s and modify your standards according to your budget. Always ask questions to your jeweller, in order to ensure that you are getting what you pay for.