You're welcome MissSugarPop33, I'm not the expert on cutting, I use a wet tile saw with a (dewalt continuous diamond blade) to cut my material, if you've never cut before you can try and call all the lapidary clubs near you and see if they will cut it into slabs for you, I use to do that before I bought a saw, they usually only charge a buck or two per slab. On leaving it outside, no it won't hurt it, it was outside for millions of years before you found it, the white stuff I haven't got a clue, someone else on here might know though, again very cool find.