This is a Pyrrhotite on Dolomite specimen from Brazil. It has a Pyrrhotite crystal that is an iron sulfide mineral and is weakly magnetic.
There are Dolomite crystals on the Pyrrhotite and it sits on Dolomite crystals all around the bottom of the specimen. No damage.
Ex Donald Zowader Collection. Price on previous label $200. Above price reflects double keystone off.