More than Just Lines on a Map: Best Practices for U.S Bike Routes
Mohs Scale of Hardness, Hardness Scale.pptx
1. Hardness Minerals Remarks
1 Talk
Scratched by a finger nail
2 Gypsum
3 Calcite
Scratched by a knife
4 Fluorite
5 Apatite
6 Orthoclase
Scarcely scratched by a knife
7 Quartz
8 Topaz
Not scratched by a knife
9 Corundum
10 Diamond
Table: Mohs Scale of Hardness