Hi Baize,
It's what is called a "Spanish Black" tomato. They are varieties that are from Spain that they call black but are not in the same catagory as what we call blacks. They are actually a brown/mahogany color but some (not all) have the green or different colored shoulders. Not as sweet as our blacks but worth trying for any serious collector or grower so you understand the difference. This particular one is from Almoguera and was so beautiful. Very firm texture and good taste. Hope that helps