Mineral

A mineral is a naturally occurring inorganic element or compound having an orderly internal structure and characteristic chemical composition, crystal morphology and physical properties such as density and hardness. Minerals are the fundamental units from which most rocks are made.

Did you know?

• Common minerals in volcanic rocks include quartz [SiO₂], anorthite feldspar [CaAl₂Si₂O₈] olivine [(Fe,Mg)₂SiO₄], magnetite [Fe₃O₄], biotite [K(Mg,Fe)₃AlSi₃O₁₀(OH)₂ and pyroxene [Ca,Fe,Mg)₂Si₂O₆]
• Obsidian (volcanic glass) is not a mineral because glass has no orderly internal structure.
• Amber is not a mineral because it is formed by organic processes, and its chemical composition can vary.
• Rocks, such as granite or sandstone, are mixtures of minerals. Their compositions can vary widely and cannot be approximated by a mineral formula.
• The Moh's Hardness Scale is used to calibrate the hardness of minerals. The list, in order from soft to hard, is as follows:

Moh's Hardness scale

1. Talc Mg₃Si₄O₁₀(OH)₂
2. Gypsum (CaSO₄·2H₂O)
3. Calcite (CaCO₃)
4. Fluorite (CaF₂)
5. Apatite Ca₅(PO₄)₃(OH-,Cl-,F-)
6. Orthoclase KAlSi₃O₈
7. Quartz SiO₂
8. Topaz Al₂SiO₄(OH-,F-)₂
9. Corundum Al₂O₃
10. Diamond C (pure carbon)