The Strunz Classification of Minerals

The Strunz classification, developed by German mineralogist Karl Hugo Strunz and updated by Ernest Nickel, organizes minerals primarily by their chemical composition, with subdivisions based on crystal structure.

The system divides minerals into 10 major classes:

1. Native Elements — minerals of single elements (gold, silver, diamond, sulfur)
2. Sulfides — sulfur compounds with metals (pyrite, galena, sphalerite)
3. Halides — halogen compounds (halite, fluorite)
4. Oxides — oxygen compounds (hematite, magnetite, corundum)
5. Carbonates — carbonate compounds (calcite, dolomite, malachite)
6. Borates — borate compounds (borax, ulexite)
7. Sulfates — sulfate and related compounds (gypsum, barite)
8. Phosphates — phosphate compounds (apatite, turquoise)
9. Silicates — silicon-oxygen compounds, the largest class (quartz, feldspar, mica)
10. Organic Minerals — organic compounds (amber, whewellite)

The silicate class (09) is subdivided by the arrangement of silicon-oxygen tetrahedra: nesosilicates (isolated), sorosilicates (pairs), cyclosilicates (rings), inosilicates (chains), phyllosilicates (sheets), and tectosilicates (frameworks).

This systematic approach allows mineralogists to predict properties of related minerals and understand evolutionary relationships between mineral species.