Have you tried Macrock? It generates random rocks exports as DXF which you can import into library objects to create a collection of rocks.
Here is a link...
http://www.laffeycomputer.com/macrock.html
![rock.jpg rock.jpg](/t5/image/serverpage/image-id/17526i1483CF3A2910B6E0/image-size/large?v=v2&px=999)
AC versions 3.41 to 25 (UKI Full 5005).
Using AC25 5005 UKI FULL
Mac OSX 10.15.7 (19G2021) Mac Pro-2013 32gbRam AMD FirePro D500 3072 MB graphics