Last modified: October 6, 2020
Moh’s Hardness Scale
Moh’s Drill and the Castle of Doom: http://www.fossweb.com/modules3-6/EarthMaterials/activities/mohsdrill.html
Last modified: October 6, 2020
Moh’s Drill and the Castle of Doom: http://www.fossweb.com/modules3-6/EarthMaterials/activities/mohsdrill.html