Your choice between 9k and 18k solid yellow gold.
Solitaire ring: approx. 4-7mm wide domed band; 2-3mm thickness; 0.25ct Natural White Diamond (round brilliant cut; F-H colour, VS clarity) in a thick bezel setting.
Stacked band: approx. 3mm wide band; 2mm thickness; 0.01ct natural white diamonds in flush setting.