The difference between brown rice and white rice is not just colour. A whole grain of rice has several layers. Only the outermost layer, the hull, is removed to produce what we call brown rice. This process is the least damaging to the nutritional value of the rice and avoids the unnecessary loss of nutrients that occurs with further processing.
Brown rice is an excellent source of manganese, and a good source of selenium, phosphorus, copper, magnesium, and niacin (vitamin B3).