Nadia & Co. · The jewelry journal
Diamond basics: the 4Cs
Small details. A beautiful difference.
Cut, color, clarity and carat weight give you a useful language for comparing diamonds. Explore each one below.
Explore below
The details make the difference
Explore the 4Cs.
Select a detail to see what it tells you about a diamond.
Cut
How light comes to life.
Facet proportions, polish and symmetry influence a diamond’s brightness, fire and sparkle. Shape and cut are different ideas: an oval is a shape.
Look at the stone in motion. A report is useful, but your eye matters too.
Color
From colorless to warmer tones.
On the D–Z scale, D–F is colorless, G–J is near colorless, and later grades show increasing body color. Fancy-color diamonds use a different system.
Compare diamonds in similar lighting and consider how your chosen metal affects the overall look.
Clarity
A closer look inside.
Clarity describes internal inclusions and surface blemishes. GIA evaluates natural diamond clarity at 10× magnification, from Flawless through Included.
A clarity grade does not guarantee that a stone looks clean to your eye. Ask to see the actual diamond.
Carat
Weight, rather than width.
One carat equals 0.2 grams. Two diamonds of the same weight can face up differently because shape and proportions affect their dimensions.
Compare the millimeter measurements as well as the carat weight.
Diagrams are illustrative, not grading tools. Screen color, inclusion marks and relative size are not representations of a particular diamond.
How should I read a grading report?
Check the laboratory, diamond origin, report number, measurements and any treatment comments. Grading systems vary: IGI uses 4Cs assessments for lab-grown diamonds; GIA introduced Premium and Standard lab-grown quality assessments in October 2025. GIA’s natural-diamond overall cut grade applies to standard round brilliants in the D–Z range.
Sources & further reading
Educational references used in these guides. Illustrations are simplified and do not grade or authenticate a gemstone.