Jouwell Diamond Score · Free diamond checker
Jouwell Diamond Score: check any diamond
Enter a grading certificate and get a score out of 100 for cut, colour and clarity, what is holding the stone back, and higher-scoring diamonds available now.
It is the same score we show on every diamond we supply, and the same as in the Jouwell Score app.
Checked recently
Certificate number
Find the diamond
We look for it in the inventory we source from first, then score it from the certificate values.
Nothing is saved to an account.
Photo or PDF
Any lab, any report
We read the grading report for you, then show you every value to check before scoring.
The certificate is used only to read its values. Jouwell doesn’t store it.
For a good photo
- Lay the certificate flat in good light.
- Fill the frame with the whole report.
- Avoid glare and shadows.
Drop the certificate here
A JPEG, PNG or WebP photo, or a PDF up to 4 MB
Reading the certificate…
This takes about 10 to 20 seconds.
How it works
How the Jouwell Diamond Score works
The Jouwell Diamond Score rates a diamond out of 100 from the values on its grading certificate. It is built on 40 years of buying and setting diamonds and on published cut, colour and clarity guidelines.
Cut. How well the stone handles light. It matters most, because a well-cut diamond looks bigger, brighter and livelier.
Colour. How white the stone looks for its size and shape. Larger stones and fancy shapes show colour more.
Clarity. Whether inclusions are visible, judged against what you can actually see at that size.
What the colours mean
A weak area counts more
A weak area pulls the score down more than strong areas push it up, so a dark, badly cut stone can’t hide behind a perfect colour grade. If any part is rated Poor, or the clarity grade is I1 or lower, the overall score can’t go above 59.
The lab matters
We take GIA, AGS, HRD and GCAL grades as printed. IGI is widely used and reliable but grades natural stones a little more generously, so natural stones graded by IGI lose 3 points. Lab-grown stones are compared with other lab-grown stones.
Missing values
Some certificates leave out details we need, such as the depth or the polish grade. We still rate every value that is there, but we don’t give an overall score from incomplete data, and we tell you what is missing. Rare shapes and fancy-colour diamonds are not scored.
The full rules, shape by shape, are in our diamond buying guide →
The Jouwell Diamond Score is our own assessment, based on decades of experience with diamonds and on published cut, colour and clarity guidelines. It is not a laboratory grade. Always rely on the diamond’s grading certificate.
Questions
Jouwell Diamond Score FAQ
What is the Jouwell Diamond Score?
A score out of 100 for how well a diamond is cut and how white and clean it looks for its size and shape. Cut counts for 45%, colour for 30% and clarity for 25%.
Which certificates can I check?
Any grading report. A certificate number from GIA, IGI, HRD, AGS, GCAL or EGL is looked up in the inventory we source from. Any other report can be scored by entering its values, or by uploading a photo or PDF of it.
Why does a diamond get no score?
When the certificate leaves out values we need, such as the depth or the polish grade, or for rare shapes and fancy-colour diamonds. We still rate every value that is there and tell you what is missing.
Is the Jouwell Diamond Score a laboratory grade?
No. It is our own assessment, read from the certificate. Always rely on the grading report itself.
Numbers are a filter, not a verdict.
They reliably catch badly cut stones, but two diamonds with the same numbers can still look different. Before you buy, look at a video of the actual stone, or ask us and we’ll review it for you.