2
2 comments on geology.com/minerals/mohs-hardness-scale.shtml
| Mohs Hardness Scale: Testing the Resistance to Being Scratched #ToothEnamel is a 5 on the #MohsHardnessScale &neo 2015-02-18 12:01:53 |
| #MohsHardnessScale: Testing the Resistance to Being #Scratched #BlackPaste #Research &neo 2015-02-17 23:37:59 |