very heavy, mica-like surface, scratch test with knife produced very fine black powder. But when I rubbed the black powder on paper it was reddish brown. Looks like graphite but it’s too heavy. Found on Dauphin Island beach Alabama this summer 2018. It is non magnetic. I couldn’t break it with a hammer.
Looks like weathered hematite to me. Reddish brown streak, high specific gravity, metallic luster, and typically none magnetic. Hematite is stronger than iron, but you still should be able to break it with a hammer. See https://en.wikipedia.org/wiki/Hematite, note the description about magnetism is a little confusing in wiki write up.
It looks like a meteorite, in particular a Chondrite. There appears to be a fused outer layer, looks greenish in the photo, around the inner material, which appears grey.