How to read a diamond certificate
Carat, colour, clarity, cut, measurements, fluorescence: what each line on a certificate means, in plain words.
A grading report lists the stone's identity and quality. Start at the top: report number, shape and measurements in millimetres. Next come the 4Cs. Carat is the weight. Colour runs from D (colourless) to Z. Clarity goes from FL to I3. The cut grade is given for round stones only. Lower down you'll find polish, symmetry and fluorescence, and for lab-grown stones the growth method (CVD or HPHT). The plot map shows where the inclusions sit. That's a lot to take in, so we made the Jouwell Diamond Score. Our gemologist rates cut, colour and clarity from 1 to 100 and combines them into one simple score.
Choosing a diamond? Our diamond buying guide gives the cut, colour and clarity numbers to look for by shape and size.