Heavy for it's size, magnetic (most of them, but not all). Trying to cut it is difficult without a diamond blade. (and slow even then). Many have signs of the immense heat-called a fusion crust.
I noticed this was your very first post - so, Welcome Aboard Lava_rock! You didn't list your state (or country) in your profile. So, you might consider jumping over to Sub-Forums: Select Your Area.... and selecting location information (i.e., clubs, hunts, finds, legends, maps, etc.) directly related to your state (or country). You might also consider adding your state (or country) to your displayed profile (SETTINGS -> EDIT PROFILE) so if you ask a question, etc. - people may have more success helping you (if necessary)...
I can't remember the term for it, but look it up on the meteorcrater in AS. It looks like, and sounds like, melted rock blown out of the earth when a meteor hits the ground. It melts, resolidifies, and is found in the area.