Moh's Hardness Scale - Education Set phenakite (They were purchased while buying

(They were purchased while buying out another rock business- and no info was with them)

Black foam has been added underneath as a protective layer

Approximate weight for 1 opal: 8g

Shaft Diameter: 8mm                                                                                                          Overall Length: 300mm

Moh's Hardness Scale - Education Set phenakite (They were purchased while buyingDescription: These Moh's hardness scales contain the 9 primary minerals of the Mohs hardness scale (excluding diamond) mounted on an identification plaque. A Mohs Hardness Scale sample kit is a collection of reference minerals with known hardness values, typically ranging from 1 (the softest) to 10 (the hardest), used to test and compare the hardness of unknown materials. Users can scratch the materials with one another to determine the relative