A walnut is a seed belongs to the genus Juglans family. Walnut consists of two bumpy lobes that look like abstract butterflies. The lobes are off white in color and covered by a thin light brown skin. Walnut has round or oblong shells that are brown in color and very hard. It is sweet and bitter in taste. Unshelled walnuts if store in a cool, dry, dark place can last for six month.