when creating this much dust. Even without asbestos, this dust is a nuisance.
Franz, I really do not know if asb was ever added to drywall, others may have more input on this. There was a time when asb was a wonderful chemical and fire retardant. It could have been added, I just do not know.
I would, wear a good breathing mask, and if in doubt, have it checked out.
Is this material or particle actually "in" the rock or a layer on either side of the rock?
Franz, I am not a doctor or profess to be one, but if its asbestos, you more than likely did not ingest enough to cause problems, BUT, I would not take in any more. ASB is an accumulative thing and is not expelled from the body, it builds up.
My father in law breathed it in for a period over 25 years and then died 30 years later. The 30 years were "no side effect" years at all.