Morgans wrote:

"George Patterson" wrote

Drywall is gypsum plaster between two layers of thick paper. The
taping/finishing compound is something else. Just read the label on the
USG
stuff I use. Limestone, water, talc (Ron's right, as usual), mica, and
vinyl
acetate polymer.

It is primarily gypsum, with very small percentages of the other stuff.

Then it's interesting that gypsum does not appear in the ingredients list.

George Patterson
He who tries to carry a cat by the tail learns something he can learn in
no other way.