Most manufacturers use the MOHS scale to test the scratch and abrasion resistance of the glaze applied to tile. The MOHS scale is based on a relative value of 1-10; with 1 being the softest and 10 being the hardest. The following are the ten standard minerals used in the scale. 1. Talc, 2. Gypsum, 3. Calcite, 4. Fluorite, 5. Apatite, 6. Orthoclase, 7. Quartz, 8. Topaz, 9. Corundum, 10. Diamond.