this is not my answer I found it from someone else but I hope it helps!
1)The simplest structure is cubic system like simple cubic ,body- centered cubic and face centered cubic in the crystal system.
2)Yes, all minerals have crystal structures because minerals have definite crystal structure. Minerals are solids that are formed naturally through the inorganic processes. some mineral properties are density, shape, color, and hardness.
3) minerals are the naturally occurring inorganic substances which have ordered atomic arrangement, they are not made by humans that's why we can't predict the specific structure of majority of minerals.
