What are the 4Cs of diamonds?
Read 7 min
The 4Cs — Cut, Colour, Clarity, and Carat — are the global language jewellers use to describe diamonds. Understanding them helps you compare quotes fairly and spot where to invest or save.
Cut — the sparkle engine
Cut is not the shape (round, oval, pear) but how well facets interact with light. An excellent cut can make a slightly smaller stone look larger and brighter.
Poor cut leaks light through the pavilion; the stone looks dull even with high colour and clarity grades.
Colour — the D to Z scale
D is colourless; Z shows noticeable yellow or brown. For 18K yellow gold settings, G–I often looks icy because the metal warms the overall appearance.
In white gold or platinum, many buyers target F–H for a crisp look without paying for top-tier D–E unless size is secondary.
Clarity — eye-clean is the goal
Grades run from Flawless (FL) to Included (I). Most jewellery uses VS or SI stones that appear clean to the naked eye.
Inspect under 10× magnification in-store. A tiny inclusion under a prong may be acceptable; one dead centre in the table is not.
Carat — weight vs spread
Carat is weight, not face-up size. A well-spread 0.90 ct can look larger than a deep 1.00 ct with a small diameter.
Prices jump at milestone weights (0.50, 0.70, 1.00 ct). Slightly under a milestone can free budget for better cut or colour.
Reading your certificate
IGI, GIA, and similar reports list the 4Cs plus fluorescence, measurements, and proportions. Match the laser inscription on the girdle to the report number when possible.
Keep the certificate with your purchase invoice — it protects resale value and insurance claims.