This fruit is actually not technically classified as a berry, but rather an aggregate fruit. Blackberries are high in dietary fiber, vitamin C, vitamin K, folic acid, and the essential mineral manganese. They are also strong in antioxidants, particularly polyphenolic compounds such as ellagic acid, tannins, ellagitannins, quercetin. Blackberries made a delicious snack alone, with yogurt or cereal or a wonderful filling for pastries and pies.