Implied exchange rate from Commodity Market

The commodities like Gold and Silver traded all over the world in Exchanges as well as in over the counter markets for 24/7.  Given that we can trade assets like Gold and Silver in demat form instead physical form we can ignore the storage cost from the cost of carry. So we have to consider the only the interest rate between the countries, where we want for see the exchange rates. Before going to convert into exchange rates we need to consider how the different exchanges quoted the contracts in their contract design. If look at Chicago , they quote the gold for troy ounce and India it is in Kg. Similarly we need to consider for the other countries before estimating respective exchange rates. Once you compare the implied exchange rates with actual exchange rates there can be seen that almost similar direction in movement. So trader can make use of the information from the commodity market for trading the exchange rates