A truffle has a rather unappealing appearance—round and irregularly shaped with a thick, rough, wrinkled skin that varies in color from almost black to off-white. The fruiting bodies present on truffles are fragrant, fleshy structures, that usually grow to about the size of a golf ball; they range from white to gray or brown to nearly black in color. There are nearly 70 known varieties of truffles, but the most desirable is the black truffle—known as black diamond—that grows in France’s Perigord and Quercy regions as well as Italy’s Umbria region. The flesh of the black diamond appears to be black, but it is actually dark brown, and contains white striations. The flesh has an aroma that is extremely pungent. The next most popular is the white truffle (actually off-white or beige) of Italy’s Piedmont region. Both the aroma and flavor of this truffle are earthy and garlicky. Fresh truffles are available from late fall to midwinter and can be stored in the refrigerator for up to three days. Dark truffles are generally used to flavor foods such as omelets, polentas, risottos, and sauces. White truffles are usually served raw; they are often grated over foods such as pasta or dishes containing cheese, as their flavors are complementary. They are also added at the last minute to cooked dishes.