Answer:
Quartz is the hardest mineral of the minerals on the table.
Explanation:
Since a scratch was produced with Chalcopyrite, Pyrite and Orthoclase but not on Quartz, clearly Quartz was the hardest mineral of the minerals that were tested. To prove this, we can search up the hardness of each mineral. Quartz on the hardness scale is 7, Orthoclase on the scale is 6, Pyrite is 6 and Chalcopyrite is 4. Quartz being the highest at 7 is the hardest of the minerals
