Before buying a diamond ring, it helps to know the Four Cs — cut, color,...

https://hatton-garden-jewellers.co.uk/7-things-to-check-before-buying-a-diamond-ring

Before buying a diamond ring, it helps to know the Four Cs — cut, color, clarity, and carat — so you get the best value for your budget. Check for a GIA grading report number to confirm quality and authenticity