for a 10 karat wedding band size 12.5, i think it is maybe one gram or maybe 1.5 grams.
the diameter of the ring i have is 22mm
giving a circumference of close to 70mm. The thickness is 1 mm and the width is 3 mm. gold has a density of 19.3 grams per cc. my ring is about a fifth of a cc.
if it was 24 karats that gives close to 4 grams of gold. my ring is only 10 karats