* Organic: Minerals are naturally occurring inorganic substances. This means they are not derived from living organisms.

* Synthetic: Minerals must be formed naturally, not created in a lab.

* Amorphous: Minerals have a defined crystalline structure. Amorphous substances lack this structure.

* Solid solution: While some minerals can form solid solutions, they are still considered individual minerals. A solid solution is a mixture of two or more minerals with a single crystalline structure.

* Liquid or gas: Minerals are always solid.

* Man-made: Minerals are natural formations, not created by humans.

In short, a mineral must be:

* Naturally occurring

* Inorganic

* Solid

* Crystalline