Oxide
Diamond is the hardest mineral and is the only one that can scratch corundum. but in my opinion corundum will scratch corundum any mineral of the same hardness will scratch the other !
It is a Mineral
Corundum can scratch almost any mineral that isn't diamond.
Pure corundum is clear in color.
The commercial name of the ruby is 'ruby rock'. In geological terms it is called as Goodletite. It is commonly found in Westland and New Zealand.
The mineral corundum.
Ruby, a variety of the mineral corundum, has a hardness of 9 on the Mohs scale of mineral hardness.
Corundum is a mineral, therefore it could not be the hardest rock.
Sapphire is a gemstone version of the mineral corundum.
Corundum.
Corundum.
According to the Mohs scale of mineral hardness, quartz (7) will not scratch any mineral with a higher number on the scale. Corundum is listed at 9. Therefore quartz will not scratch corundum, but corundum can scratch quartz.