Question

A mineral of unknown hardness scratches a human fingernail. What is the hardness of the mineral?

1) 1
2) 2
3) 3
4) 4

Answer 1

The mineral's hardness is greater than that of a fingernail, which is 2.5 on the Mohs' scale, indicating a hardness of 3.

Step-by-step explanation:

The hardness of a mineral is determined using the Mohs' scale of mineral hardness. Since the mineral in question can scratch a human fingernail, its hardness must be greater than that of a fingernail, which is approximately 2.5 on the Mohs' scale. Therefore the correct answer is option 3, which corresponds to a hardness of 3 on the Mohs' scale.