Depends on the rock. A piece of dry pumice just might!
George Spagna **********************************************
Department of Physics * *
Randolph-Macon College * "I like to keep an open mind, *
P.O. Box 5005 * *
Ashland, VA 23005-5505 * but not so open my brains fall out." *
* *
phone: (804) 752-7344 * - Arthur Sulzberger *
FAX: (804) 752-4724 * *
e-mail: gspagna@rmc.edu ********************************************** http://www.rmc.edu/~gspagna/gspagna.html