There are several ways to tell minerals apart from each other. An obvious one is colour, or shape of crystal. However, one very useful property is hardness.
In 1812, Mohs arranged ten minerals in order of hardness, so each will scratch those lower in the scale. This is still used today. It is not a regular scale. There is a far greater gap between diamond and corundum, than between any other two. But it is a useful way to measure the property of hardness. I have not given the Mohr hardness of any minerals (except on this page), but you can find them in any serious book on minerals.