14.4: Minerals

Last updated
Save as PDF

Page ID: 16162

Michael E. Ritter
University of Wisconsin-Stevens Point via The Physical Environment

\( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\)

A mineral is a naturally occurring inorganic substance with a unique crystal structure. The physical and chemical composition of a mineral is consistent between samples. There are nearly 3000 minerals, only 20 are common, and 10 make up 90% of the minerals of the crust.

Minerals may be composed of a single element, like gold (Au) or a combination of elements. Minerals composed of more than one element are bound together by electrical bonding. All minerals formed by more than one element are therefore bound together by positive and negative ions. By far the most abundant ions in minerals are the positively charged silicon (Si) and negatively charged oxygen (O). Silicon and oxygen are the foundation of the silicate minerals.

The most important mineral family is the silicates. The silicates are a combination of silicon, oxygen, and another element. Depending on the element, the resulting mineral's density and color can vary considerably. The silicates are subdivided into the ferromagnesian and the nonferromagnesian (or aluminosilicates). Table \(\PageIndex{1}\) gives examples of other important mineral groups found in the crust.

Table \(\PageIndex{1}\): Important Mineral Families of the Crust
Type & Compound	Examples
Silicates - nonferromagnesian (Silicate ion; lack iron and magnesium ions)	Pyroxene Muscovite Mica Orthoclase (Potassium) feldspar Plagioclase feldspar Quartz
Silicates - ferromagnesian (Silicate ion+iron and magnesium ions)	Olivine Hornblende Biotite Mica
Oxides (Oxygen + element(s))	Limonite Hematite Magnetite
Sulfides (Sulfur + element(s))	Galena Pyrite Chalcopyrite
Carbonates (Carbon-oxygen ion + element(s))	Calcite; dolomite