Yeah, I'm somewhat familiar with tourmaline and it's definitely not as dark as I have seen. Much more metallic. It looks a lot like carborundum but it doesn't have any iridescence.
Discussion
So many varieties. Be curious to know if you do get it identified. Just to know if I actually still have a little kniwledge as a geologist!
Well, I had a geologist friend look at that piece. He's leaning the same as you but can't clearly identify it without proper tests and I am not curious enough to pursue it any further. I just want to incorporate it into some artsy thing. I did get a nice lecture about not asking the guy who sold it to me. So that was fun. 😅
It took me a long time to get a straight answer on this... but it's black kyanite.