Join our newsletter today and receive a special 10% discount code for your next purchase.
A lab-grown diamond usually comes with a report, and it is worth understanding what that report is for. It describes one stone in careful detail: its proportions, its colour, its clarity and its weight. It is a description, not a price and not a promise about the finished ring. Reading it properly takes a few minutes, and those minutes are the difference between taking the stone on trust and understanding it.
What a certificate actually is
A grading report is an independent description of a single diamond. It is written by a laboratory rather than by the jeweller, and that is the whole point of it. A trained grader examines the stone under controlled conditions and records what is there, in a standard language that means the same thing wherever you are. The report is a second opinion from someone with no stake in the sale.
That is why we work with certified stones and with GIA-certified specialists. Not because a certificate makes a diamond better, but because it lets you check the stone against something other than our word.
The four things a report measures
Almost every diamond report is built around the same four measures, known as the 4Cs.
| Measure | What it describes |
|---|---|
| Cut | How well the stone's proportions and facets return light |
| Colour | How colourless the stone is, graded on a defined scale |
| Clarity | How free the stone is of internal inclusions and surface marks |
| Carat | The weight of the stone |
For a natural diamond, colour is graded on a scale that runs from D, which is colourless, down through the alphabet as more colour appears. It is worth knowing that D–Z is the natural-stone scale; a lab-grown stone is graded within its own conventions rather than being dropped into the same run.
Where a lab-grown report differs
This is the part that is often glossed over, so we will be precise about it. GIA assesses natural and lab-grown diamonds against the same 4Cs. The measures are the same, and the language is the same, because the material is the same. What can differ is the form of the report itself. A report for a lab-grown stone may be presented differently from one for a natural stone, and it will identify the stone as lab-grown.
So the honest reading is this: the grading is comparable, and the paperwork is not necessarily identical. If someone tells you the two are graded identically in every respect, that is a simplification worth questioning, kindly. The useful question is not whether one report is better, but whether you can see the report for the stone you are being offered.
What a report does not tell you
A certificate is a description of a stone. It is not a valuation, and it does not tell you what a diamond is worth or what it should cost. It says nothing about the setting, the metal, or how the finished piece was made. It will not tell you whether the design suits the hand it is going on.
Those are judgements, and they are made by people, in conversation. A report is the beginning of that conversation rather than the end of it.
How to use one
Ask to see the report for the specific stone in front of you, and read the four measures rather than the headline number alone. A larger carat weight with a poor cut can look duller than a smaller stone cut well. Then ask what the report does not cover: how the stone will be set, how the piece will be made, and how it will wear.
If you are weighing a lab-grown stone against a natural one, our guide to lab-grown diamond engagement rings takes that comparison further, and the lab-grown guide collects the rest.
Frequently asked questions
Does a certificate prove a diamond is real?
A certificate describes the stone it was written for, and a lab-grown report will say so plainly. It is a description by an independent laboratory rather than a proof of anything, which is exactly what makes it useful.
Is a certified diamond better than an uncertified one?
The certificate does not change the stone. It gives you a second, independent description of it, which makes the choice easier to make with confidence.
Is a report the same as a valuation?
No. A grading report describes the stone's qualities. A valuation is a separate document concerned with value, usually for insurance.
Can the report form differ for a lab-grown stone?
Yes. GIA assesses both against the same 4Cs, but the form of the report may differ, and the report will identify the stone as lab-grown.
Talk it through with us
Choosing a stone is easier when you can see the paperwork beside the diamond and ask questions about both. Book an appointment and bring any report you have been given, and we will walk through it with you.
Related posts
A lab-grown diamond is a real diamond: same material, same optical properties, independently graded. Here is what the difference actually is.
What the same budget buys in lab-grown versus natural — and whether to spend the difference on carat, cut grade or the setting.
Moissanite, lab-grown and natural diamond compared on hardness, fire, appearance and cost — without the sales pitch.
The diamond industry has undergone a seismic shift, and if you haven't been paying close attention, you may have missed...
They are not “fakes,” imitations, or look-alikes such as cubic zirconia. A lab-grown diamond is physically, chemically, and optically identical to a diamond mined from the earth. They have the same carbon atom structure, the same hardness, and the same magnificent sparkle.
Let’s start with the most important fact: Lab-grown diamonds are 100% real diamonds.
Your expert guide to the 4 Cs of lab-grown diamonds in Chichester. Learn about cut, colour, clarity & carat to create your perfect engagement ring. Book now.
Discover why lab-grown diamonds are the ethical & sustainable choice in Chichester. Create a beautiful, conflict-free engagement ring.
Discover lab-grown diamonds in Chichester. Our guide explains why they are the perfect, ethical choice for your bespoke engagement ring.