Sounds like haematite to me too, Sue. Also called bloodstone - bigger pieces have, or can develop (not sure which), small red flecks. I think I know the kind of bracelet you're talking about - I had one at one stage - and the stones have been 'finished' with a metallic grey sheen, so there's no red in them.
Haematite is very grounding - some people find it a bit too heavy, even depressing (there's a thread about this somewhere on this forum). If you're the airy-fairy type though you'll find it beneficial. I'm a Gemini and a generally hyper, wired-to-the-moon type of personality, and I find it has a lovely calming, grounding effect. I lost the bracelet, but I have a piece of haematite in a small dish of 'dark' stones (smoky quartz, obsidian, chalcedony etc.) on my bedside locker and I think they help me sleep better - something I used to have a lot of trouble with.
Kate