the natural stuff is in clumps that your not able to breathe, and yeah asbestos is natural and almost everywhere there's rocks. it's usually in long fiber like strings. even when it's broken up, it's not particle size and airborne. it's usually bonded together.

it's that stuff that was industrialized and refined. that stuff that can become airborne and inhaled. One particle that gets absorbed might stay with you forever but it's usually the build up of many exposures that causes the problem.

so many older houses have it in the attic and siding. it's not going anywhere