How to Competitively Price Gold Jewelry?

The pricing formula I use for sterling is not quite working for my
handcrafted gold pieces. That formula is: (double material costs +
time) plus 10% = wholesale price When I use this for gold, my prices
turn out too high. I think the variable involves my material cost
for gold - which includes milling and casting charges- that I’m
doubling. Is this wrong? Should I be weighing out my pieces and
calculating a markup that way? What would a formula be?

Thanks in advance for all your help,
Anastasia Trainer