I like this idea, even if it was posted before, looking in the other post i found it wasn't too much developed. It would be an interesting event to have, idk about the aliens but a new kind of magic metal sounds interesting. What I saw on the other thread is that it used a simple function to check the surface for undeveloped area before hitting down.
Maybe a smoke particles going way up from the place and setting some trees on fire would make it more realistic and easy to spot once it happened.
I personally don't think it should be too "magic", it should just be like, some sort of... space material thing, like, there should be a lot of new materials (a LOT) which represent the ground of other planets, however it would be more powerful than diamond. If you want to give it some special feel, you could add a sign inside of it that said "Your Lucky Stars Are Here For You"