Traditionally rice, like beans, had to be picked over to check for and discard stones and pebbles. But modern-day commercial rices have usually been well cleaned and sorted before being bagged and shipped, so there’s rarely any need for a preliminary check of the rice. To make sure, if you are using a rice that is new to you, place some in a sieve and look at it closely. It should (and usually will) be of even quality, with no stones or other foreign particles.
The second traditional step is to wash the rice thoroughly in several changes of cold running water. Originally, this ensured that any dirt or dust from the threshing floor or impurities from storage would be washed away. Again, with modern cleaning and storage, these reasons may not apply. But preliminary washing also wets the rice and washes off any loose starch prior to cooking. We think it makes a positive difference in the texture of the cooked rice, making it less sticky and helping it cook more evenly. It is also true that after years of washing rice and watching people in Asia wash rice before cooking, we somehow don’t feel comfortable cooking unwashed rice.