The major difference between peaches and nectarines is the skin. Peach skin is fuzzy, while nectarine skin is smooth and has more of a red color. In cooking and baking, there is no difference between the two beneath the skin, and they can be used interchangeably in recipes.
When eaten raw, nectarines are sweeter and more firmer, more flavorful and have a stronger smell than peaches. Nutritionally, nectarines contain twice the vitamin A, much more potassium and slightly more vitamin C than peaches. Nectarines are slightly smaller than peaches and are more vulnerable to the diseases of brown rot and bacterial spot.
There is a wide variety of cultivars of both nectarines and peaches, with varying characteristics of the fruit. Some believe that nectarines are a form of the peach, while others think the nectarine is a naturally occurring mutation of the peach. Darwin described both peach trees that grew nectarines and nectarine trees that grew peaches. Both nectarines and peaches are believed to have originated in China 2,000 years ago. They were both grown in ancient Persia, Greece and Rome. The peach was named around 300 B.C., while the word "nectarine" first appeared in the English language in 1629.