Abrasive grain, grit size 500F is a tumbling grade silicon carbide abrasive. (Fine grit stage.) Use one tablespoon grit per pound of rock in your tumbler. See articles on tumbling for more information. Abrasive grain grit size 500F is sold in one pound packages. A five pound package of 500F is available for $36.00. Please send an e-mail if interested and a change can be made on your order.