Why are there a wide range of colours, hardness, crystal forms, luster and density found in minerals?

A wide range of colours, hardness, crystal forms, luster, and density is found in minerals because of the high levels of variations in physical and chemical conditions under which a mineral is formed.

NOTE – A mineral is a combination of certain elements which are highly dependent on the physical and chemical conditions. The wide variety found in the properties of minerals is possible because of these different physical and chemical conditions.