Mineralkomposition

Mineralkomposition refers to the chemical makeup of a mineral, describing which elements are present and in what proportions. In geology and materials science, composition is usually expressed as a chemical formula or as oxide weight percentages that reflect the dominant constituents and any substitutions that occur within the crystal structure. The composition, together with crystal structure, determines the mineral's properties and classification.

Many minerals exhibit solid solution, where different elements replace each other in the crystal lattice without changing the mineral class. Common examples include the olivine series (forsterite to fayalite) and the plagioclase feldspar series (albite to anorthite). End-members represent the pure end of a solid-solution series, while real minerals often lie along a spectrum between them. Composition can also be reported as empirical formula derived from stoichiometry or as oxide/elemental percentages for analytical purposes.

Determining mineral composition involves laboratory techniques such as electron probe microanalysis (EPMA) or energy-dispersive X-ray spectroscopy (EDS) coupled with scanning electron microscopy, as well as X-ray diffraction for phase identification. X-ray fluorescence (XRF) provides bulk oxide compositions. Trace elements and isotopic ratios may require LA-ICP-MS or SIMS. Mineral databases record typical and measured compositions for reference.

Composition influences properties such as density, hardness, color, and refractive index, as well as chemical stability and metamorphic or igneous histories. It is essential for classifying minerals, identifying rock assemblages, guiding ore exploration, and informing materials science applications such as ceramic and glass formation.

Overall, mineral composition describes the quantitative chemical makeup of a mineral, the degree of solid-solution, and the relationships to end-members and substitutions that shape mineral diversity.