Start with the setting style, then choose the diamond to fit it. Decide first whether you want a solitaire, a halo, pave or side stones, since that sets how much bright metal and how many small diamonds surround the center. Next, pick the shape the head is made for and a size that suits the hand. White gold is plated with rhodium for its bright color, a layer that wears and can be replated, so it suits someone happy to trade that for a lighter ring than platinum. Once you order, Rare Carat's New York team inspects your diamond under a microscope and matches its laser inscription to the grading report.
Aim higher on color than you would for yellow or rose gold, because white metals show warmth in a diamond more. The upper end of near colorless, or colorless if it fits the budget, keeps the stone looking icy against bright rhodium, and that matters most for larger diamonds and for step cuts such as emerald and asscher, which show color more. Toward the lower end of the G to J range, some eyes will notice a soft tint beside the metal. Cut still comes first for sparkle, and clarity only needs to be eye clean.
Both look white, but they behave differently. Platinum is naturally white, so it never needs plating; it is denser and heavier, hypoallergenic for most people, and when scratched it forms a soft patina rather than losing metal. White gold is lighter on the hand, and in 14K it is harder and more scratch resistant than in 18K. Choose white gold if you like a lighter ring and do not mind an occasional replating, or compare platinum settings if you would rather never think about the coat.
White is a natural backdrop for designs full of small diamonds, where the metal almost disappears behind the stones. Browse white gold pave settings or white gold halo settings to see that effect.
Shape and setting should agree. Rounds sit happily in four or six prongs. Pears, marquises and princess cuts want V prongs or a bezel at their points and corners. An oval or emerald can run east west across the finger for a modern twist. Against a colorless stone, white prongs nearly vanish, so the outline of the diamond reads cleanly, one reason this metal flatters fancy shapes with crisp edges.