Beyond the 4C’s: Why certification is a guide, not a guarantee.
At first glance, buying a diamond may seem straightforward. Two diamonds with identical 4C grades (cut, colour, clarity and carat), certified by the same laboratory, should in theory be equal in quality and value. The reality is more complex. While the 4C’s provide an important framework for understanding diamonds, they are not an exact science, especially when it comes to colour and clarity.
The Subjectivity of Diamond Grading
Unlike carat weight, which is measured with precision, colour and clarity are assessed visually. This process naturally involves human judgement, making it subjective and sometimes inconsistent. There is no universal system like centimetres or kilograms, which means two diamonds with identical certificates may not appear the same in person.Â
It’s not unusual for grading to vary slightly between laboratories, or even within the same lab. One diamond may appear brighter or cleaner to the eye than another, despite sharing the same grade on paper. These differences in appearance can directly influence how a diamond is valued.Â
Certification as a Guide
Certification remains an essential part of buying a diamond, but it should be seen as a guide rather than a guarantee.
A certificate provides valuable information about a diamond’s proportions and grading, but it cannot capture the overall beauty and brilliance revealed when the diamond is in front of you.Â
The Gregory Jewellers Standard
That is why at Gregory Jewellers, every diamond is personally inspected by our specialists.
Beyond the certificate, we assess each diamond by eye to ensure it meets our own high standards of beauty, quality and brilliance.Â
Because when it comes to choosing a diamond, numbers and letters on a page are only the beginning. What truly matters is how the diamond looks and how it sparkles in real life.
