What are they? Minerals are naturally formed inorganic solids with a crystalline structure and a definite chemical composition. Simple right? It actually kind of is...

Naturally Formed “Natural” things are those that are formed by natural earth processes.

Naturally Formed This is opposed to man-made things

Inorganic Inorganic means it is not now and never has been alive.

Solid This means that under typical conditions on earth, the item is a solid (defined shape and volume) Not a liquid or a gas.

Crystalline Structure Minerals have crystal structures, which means all of the atoms in a mineral are arranged in an orderly, repetitive pattern. Kind of like those key chains.

Crystalline Structure There are different types of crystal structures

Definite Chemical Composition Each mineral has a chemical make-up, or formula. It is made of one or more elements.

Definite Chemical Composition Some minerals are “pure” or made of one element: Gold, Iron, Silver Sulfur

Definite Chemical Composition Most are made of combinations of elements called compounds. There are more than 4000 known minerals on earth. Each has it’s own chemical formula, or recipe. Pyrite: FeS2 Quartz: SiO2

Tomorrow We’ll talk about how to identify minerals, and how they’re used.