Thread: 1$ estate sale find, What is it? P.S. mother in-law bought it for me!

My sweet mother in law, who for 30 plus years has indulged my hobbies, found this for me at a local estate sale. She paid all of 1$ for it. When I first held it it was so worn and loaded up that it appeared to be an old carborundum (it is just a hair bigger than one), but when I later looked closer at it I saw that the lamination/layers were not even and figured this was a natural cut stone. After I worked it over with a flattening stone, I could see its true color. Now I still have no idea what it is. It seems to be fairly old, The box had no markings. The stone itself is probably about 1K-3K, it feels fairly aggressive. Thanks Todd