The current price of a grain of gold is about $2.71

That is based on the current* price of a troy ounce of gold on 05/02/2014 of $1,300.00

There are 480 grains in a troy ounce, so the price of a grain is the the commonly found price of an ounce divided by 480

There are aproximately 31.1 grams in a troy ounce, so the current price of a gram of gold is about $41.80