Final answer:
Quartz, with a hardness of 7 on the Mohs scale, can scratch calcite, which has a hardness of 3. The Mohs hardness scale is qualitative, not representing the hardness of minerals in multiple factors.
Step-by-step explanation:
On the Mohs hardness scale, quartz has a hardness of 7 and calcite has a hardness of 3. This means that quartz can scratch calcite.
The Mohs scale of mineral hardness is qualitative, indicating that a mineral with a higher number can scratch any mineral with a lower number. However, it does not quantify how much harder one mineral is compared to another.
Therefore, it is not accurate to say that quartz is four times harder than calcite, merely that it is harder because it has a higher number on the scale.