What type of reaction is 2 Al2O3(s) → 4 Al(s) + 3 O2(g)

Decomposition or cracking

Explanation:

 Given reaction:

           2Al₂SO₃  →  4Al  + 3O₂

This reaction is a decomposition or cracking reaction.

In such a reaction, two or more products are formed from a single reactant; e.g;

             A  →  B + C

The breakdown of  a compound into component individual elements or other compounds falls into this type of reaction.

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).