Guide To The Four Cs of Diamonds by Genesis Rare Diamonds In the world of diamonds, there are four basic areas for evaluation which are commonly-known as “The Four C's” – cut, clarity, colour and carats. The Four C's are perhaps the most well-known standards for diamond buyers who are in the market for a stone that meets their specifications. in Public bookmarkswith click_this_linkgenesis_diamondsgenesis_rare_diamondsinfo_about_genesis_rare_diamonds Note: In the world of diamonds, there are four basic areas for evaluation which are commonly-known as “The Four C's” – cut, clarity, colour and carats. The Four C's are perhaps the most well-known standards for diamond buyers who are in the market for a stone that meets their specifications.