Nutrional and other info from Wikipedia
Obsidian Berries are a wonderful large blackberry with great flavor. The soft fruit is popular for use in desserts, jams, seedless jellies and sometimes wine. It is often mixed with apples for pies and crumbles.
Good nectar producers, blackberry shrubs bearing flowers yield a medium to dark, fruity honey.
Blackberries are notable for their high nutritional contents of dietary fiber, vitamin C, vitamin K, folic acid – a B vitamin, and the essential mineral, manganese
The blackberry is known to contain polyphenol antioxidants, naturally occurring chemicals that can upregulate certain beneficial metabolic processes in mammals. The astringent blackberry root is sometimes used in herbal medicine as a treatment for diarrhea and dysentery. The related but smaller dewberry can be distinguished by the white, waxy coating on the fruits, which also usually have fewer drupelets. (Rubus caesius) is in its own section (Caesii) within the subgenus Rubus.