Corundum is the hardest mineral in nature after diamond. For this reason it can only be scratched and worked by it. Mohs' hardness scale proves that corundum is indeed a very hard mineral and almost impossible to scratch. This scale states that the corundum has a hardness of 9.0, which indicates that it cannot be scratched by a drill.
Using the same scale, we can find out the hardness of the mineral exposed in the question. The mineral can be scratched by a drill, which means it has a hardness lower than 8.5, and the mineral cannot be scratched by a nail, which indicates that it has a hardness greater than 6.5. Based on this data, we can guarantee that this meniral is softer than the corundum.
The mineral has a hardness greater than 6.5 (steel nail) and less than 8.5 (drill bit). All other choices have a hardness less than 8.5 but corundum has a hardness of 9.0. *Mohs hardness scale
heat will flow from your hand (the warmer object) to the cup (the colder object), and your hands will start to feel cold because their losing heat energy
