Consider the unbalanced equation for the oxidation of aluminum.

_al + _o2 mc031-1.jpg _al2o3

which sequence of coefficients should be placed in the blanks to balance this equation?
2, 3, 1
1, 3, 2
4, 3, 2
3, 2, 3

answer is: naturally occurring solid, inorganic compound or element is mineral.

minerals usually have crystalline form, that means than crystal constituents (atoms, molecules or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions.

for example magnetite is a mineral of iron oxide (fe₂o₃).

calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (caco₃).

dolomite is an   carbonate mineral composed of calcium magnesium carbonate (camg(co₃)₂).