Lab-grown diamonds are subject to the same grading standards as mined diamonds when it comes to their clarity, colour, cut and carat weight. They are awarded a rating and to help you understand what the ratings mean we've included a handy guide below.
The ratings for clarity and colour have sub-ratings to further distinguish the quality of the diamonds. The scales go from left to right, so the diamonds on the left-hand side of the scales are the highest-quality diamonds available - these diamonds are the most expensive.
Inclusions are characteristics that occur inside the gemstone. When a diamond is forming, small crystals can become trapped. As a crystal grows, it can develop irregularities in its atomic structure. The size, position and visibility of inclusions can have a significant impact on diamond clarity.
Inclusions are usually called 'flaws' because this means the diamond cannot be graded as 'internally flawless' but the presence of inclusions doesn't mean the diamond is 'damaged' and some inclusions should be expected. Each piece of diamond jewellery has its clarity, colour and carat weight ratings listed in the product description. View our diamond jewellery.
Clarity - Understanding the Ratings
- FLAWLESS (F): No inclusions or blemishes of any sort are visible to a skilled diamond grader using 10x magnification.
- INTERNALLY FLAWLESS (IF): No inclusions and only blemishes are visible to a skilled diamond grader using 10x magnification.
- VERY VERY SLIGHTLY INCLUDED (VVS1 and VVS2): Inclusions are difficult for a skilled diamond grader to see using 10x magnification.
- VERY SLIGHTLY INCLUDED (VS1 and VS2): Inclusions are noticeable to a skilled diamond grader using 10x magnification.
- SLIGHTLY INCLUDED (SI1 and SI2): Slight inclusions are noticeable to a skilled grader using 10x magnification.
- INCLUDED (I1, I2 and I3): Inclusions are noticeable to a skilled grader using 10x magnification. I3 diamonds have the largest amount of inclusions.
Colour - Understanding the Ratings
Diamond colour is graded in terms of how 'white' or 'colourless' a diamond is and ranges from D-Z. While the diamond colour chart provides an example of how each grade appears, depending on the diamond’s cut, carat weight and shape, the colour might appear different among diamonds.
- EXCEPTIONAL WHITE + (D): These diamonds are considered 'colourless.'
- EXCEPTIONAL WHITE (E): These diamonds are considered 'colourless.'
- RARE WHITE + (F): These diamonds are considered 'colourless.'
- RARE WHITE (G): These diamonds are considered 'near colourless.'
- WHITE (H): These diamonds are considered 'near colourless.'
- SLIGHTLY TINTED (I): These diamonds are considered 'near colourless.'
- SLIGHTLY TINTED WHITE (J): These diamonds are considered 'near colourless.'
Cut - Understanding the Ratings
- POOR: Poor cut diamonds yield nearly no sparkle, brilliance or fire. Entering light escapes from the sides and bottom of the diamond.
- FAIR: Fair cut diamonds offer little brilliance, as light easily exits through the bottom and sides of the diamond. Diamonds of a fair cut may be a satisfactory choice for smaller carats and those acting as side stones.
- GOOD: Good cut diamonds showcase brilliance and sparkle, with much of the light reflecting through the table to the viewer’s eye. These diamonds provide beauty at a lower price point.
- VERY GOOD: Very good cut diamonds offer exceptional brilliance and fire. A large majority of the entering light reflects through the diamond’s table. To the naked eye, Very Good diamonds provide similar sparkle to those of Excellent grade.
- EXCELLENT: Excellent cut diamonds provide the highest level of fire and brilliance. As almost all of the incoming light is reflected through the table, the diamond radiates with magnificent sparkle.
Carat Weight - Understanding the Sizing
The diagrams below demonstrate the difference in size between the most common carat weights.