Figuring the cost of gold

Can I share my method of working of the price of the gold content on
my creations, it is simple. Over here we are sold gold by Gram price
so this is how I work out costs:

  1. I note the cost of the sheet and wire I purchase, say 100 grams @
    8 per gram = 800

  2. I weigh the finished article, say 80 grams, which leaves 20 grams

  3. The 20 grams scrap has a resale value of 6 per gram equalling

  1. So my original 100 grams cost me 800, my return on reselling the
    scrap is 120 so this means my 80 grams used on the finished article
    actually cost me 800 minus 120, which is 680,

  2. So the price I would charge per gram of gold is 680 divided by 80
    which equals 8.50,

I would round up the gold price to 9 to cover any losses incurred. I
hope this makes sense and is of use to someone.

Regards James Miller