I found this rock and managed to break it in half. It is black on the exterior but silver looking inside with some speckles of what looks like fool's gold. It is very heavy for a rock, twice as heavy. It weight 900g and I have it exposed to the element for 2 weeks now and it's not getting rusty or anything. I have an earth magnet attached to a 3 foot thread and when the rock gets to about 1 inch of the magnet, the magnet moves towards the rock and stick to it. So I imagine it's got a bit of iron? But the silvery thing, anyone knows what it could be? I took some picture, and hopefully this will help. Thanks for any help you can provide.