This is a CDV photo of a young woman, taken by H. A. Krull in Neu-Strelitz, Germany. What I find interesting about this is the hat she is wearing. In our eBay listing we called it a "Santa Claus" hat, but I'm sure it's not. It has a fringe with some sort of plume behind it, and they are probably white. The cap is a dark color, but which dark color is anybody's guess. She is also wearing a long necklace, perhaps with a locket, earrings, and a ring on her right hand.
Neu-Strelitz is north of Berlin.
On the back of this card is photographer information and a couple of medallions. Photographers, especailly European photographers, would frequently include copies of awards they had won on the backing of the photograph. One of the medallions on this one has a date of 1863.
If this were an American CDV, I'd estimate it from the 1880s, just by the physical characteristics of the photo and the backing. It's possible this is from the 1880s also, but since it's from Europe I can't be positive. It may be earlier. But I think 1880s would be a good estimate. No matter what - it's old.