That is sweet of Aggie to attempt to become a high end chemist, but not necessary. At one time, about a year ago gold cholride could be found for about 7 dollars a gram. Just thought I would give it a try.
The 13 dollar price is determined by purchasing an ounce of gold cholride; price depends on the market price, which changes from hour to hour (almost). When I talked to the source it was $362 an ounce. An ounce contains 28.35 grams of gold. Sure beats $40 dollars a gram.
Appreciate folks looking into this for me.
I believe the ounce used for precious metals is the Troy ounce which is 31.1 grams.