2357 - SCALE OF HARDNESS COLLECTION 9 PCS. SET WITHOUT DIAMOND - 9 SPEC.

This collection is the traditional Mohs Scale which assigned a “hardness” to ten key minerals with talc #1 (the softest) and diamond #10 (the hardest). The first 9 minerals are included in this set. The nine specimens are approximately 1” X 1.5” and are number-coded. Grades 6-12.  Geology is a required STEM subject.