1. Crystalline Solids:

* Have a highly ordered, repeating three-dimensional arrangement of atoms, ions, or molecules.

* This ordered structure gives them specific shapes and melting points.

* Examples: table salt (NaCl), diamonds, ice, metals

2. Amorphous Solids:

* Lack a long-range, ordered structure.

* Their atoms are arranged randomly.

* They often lack a specific melting point and soften gradually over a range of temperatures.

* Examples: glass, rubber, plastics, wax

There's also a third, less common category:

3. Quasi-Crystalline Solids:

* These have a highly ordered structure, but it does not repeat in a simple, periodic way.

* Their atoms form complex, non-repeating patterns.

* Examples: some alloys

So, to answer your question directly, the vast majority of solids fall into the categories of crystalline and amorphous.