When assessing an 18kt white gold piece, look for '18K,' '750,' or '18ct' stamped on the metal: these are the standard purity marks used by country of manufacture, all confirming the same 750 parts per thousand fine gold content.
Visually Speaking
The cocktail ring has never required a single large stone to make its point. Clusters, halos, and graduated arrangements have long delivered equivalent scale through entirely different means.
Stone Story
The 4Cs, cut, color, clarity, and carat weight, are the universal grading framework for mined diamonds, developed and standardized by the Gemological Institute of America in the mid-20th century and applied globally across the diamond trade ever since.