Excel Formula - Set Gram Price automatically

so does the price vary if the item is something else, for example, silver?
if not, something as simple as =C2*x where x is the value of the per gram price.

EDIT: BTW, put that in cell D2, then copy down, and format D2 as currency.

In D2

=C2*$G$1 and drag it down

	A	B	C	D	E	F	G
1	KIND	ITEM	GRAMS	PRICE		Gram Price	304.26
2	Gold	Ring	17.9	5,446.25
3	Gold	Ring	25.3	7,697.78
4