ok with gold at say 1,142 an (troy) oz -- divided by 31.1 grams (grams per troy oz) -- pure gold is worth $36.72 per gram at current melt value
once you know the current melt value the trick is to figger out just how much pure gold you got .
the items actual weight - times its gold purity % will tell you how much real gold you got
lets try this exsample --- say you found a 20 gram --18 k gold ring --(24 k is pure gold -- so 18k -- 18 / 24ths pure gold --so 3/4 pure --- 18 divided by 24 is .750* ---20 x .750 = 15 grams of pure gold x 36.72 =thats $550.80 at full melt value -- now most dealers will not pay full melt * keeping a certain % for themselves as their cut or profiet margin ( a small amount is reasonible of course since bussiness is bussiness --(but by knowing what you got you are better able to tell if your getting hosed or if its a fair offer-- and to shop around a bit -- if you can go in saying -- ok I got 20 of grams of 18 k -- , 15 grams of pure gold and spots 1,142 -- thus 550 in value --what will you offer me --its cut and dry lets get down to bussiness --cuts a lot of bs out of the way --make a offer on 550 worth of gold )