Detecting for gold in a gold field? And it's highly magnetic, not just mildly? Very possible that it's magnetite. I don't see a fusion crust on your sample--that's often a sign of a meteorite.
Iron oxide ore, magnetite or hematite, if you do t have a streak plate use the bottom of an unglazed mug, if red streak hematite. No streak maybe magnetite. The magnet is not necessarily an indicator of magnetite. I have picked up quite a few of these in the desert floor.
That's easy enough. Do it the way man has been doing it forever. Throw it on the grill for an hour then drop it in a bucket of cold water. Should shatter like a bad alibi.