The crustal ratio of silver to gold is 17.5:1. The gold/silver price ratio is often analyzed by traders, investors and buyers. In Roman times, the price ratio was set at 12 or 12.5 to 1. The gold-silver ratio refers to the ratio investors use to determine the relative value of silver to gold. Put simply, it is the quantity of silver in ounces needed to buy a single ounce of gold.