from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A scale for classifying minerals based on relative hardness, determined by the ability of harder minerals to scratch softer ones. The scale includes the following minerals, in order from softest to hardest: 1. talc; 2. gypsum; 3. calcite; 4. fluorite; 5. apatite; 6. orthoclase; 7. quartz; 8. topaz; 9. corundum; 10. diamond.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A scale of the hardness of minerals based on their ability to scratch one another
After Friedrich Mohs (1773-1839), German mineralogist.(American Heritage® Dictionary of the English Language, Fourth Edition)