A mineral is characterized by a constancy of composition and of
properties which sets it apart from rocks which vary widely. Minerals
may be metallic, like pyrite, or non-metallic, like barite; they may be
ore, like galena, or rock-forming, like quartz or feldspar; they may
show crystal faces, or they may be fragments with rounded or broken
surfaces. A favored definition teaches that “a mineral is a naturally
occurring, inorganic substance having a definite chemical composition
and definite physical properties, within limits.” The Missouri minerals
listed herein include:
Quartz
Mica
Calcite
Dolomite
Sphalerite
Galena
Barite
Marcasite
Carnotite
Tyuyamunite
Pyrite
Hematite
Limonite
Gypsum
Pyroxene
Orthoclase feldspar
Microcline feldspar
Plagioclase feldspar
Metatorbernite