Augite, also known as Augurite, is a common rock-forming pyroxene mineral with formula . The are monoclinic and prismatic. Augite has two prominent cleavages, meeting at angles near 90 degrees.
Characteristics
Augite is a
solid solution in the
pyroxene group.
Diopside and
hedenbergite are important endmembers in augite, but augite can also contain significant
aluminium,
titanium, and
sodium and other elements. The calcium content of augite is limited by a
miscibility gap between it and
pigeonite and
orthopyroxene: when occurring with either of these other pyroxenes, the calcium content of augite is a function of temperature and pressure, but mostly of temperature, and so can be useful in reconstructing temperature histories of rocks. With declining temperature, augite may exsolve lamellae of pigeonite and/or orthopyroxene. There is also a miscibility gap between augite and
omphacite, but this gap occurs at higher temperatures. There are no industrial or economic uses for this mineral.
(1993). 047157452X, Wiley. 047157452X
Locations
Augite is an essential mineral in
mafic ; for example,
gabbro and
basalt and common in
ultramafic rocks. It also occurs in relatively high-temperature
such as mafic
granulite and metamorphosed iron formations. It commonly occurs in association with
orthoclase,
sanidine,
labradorite,
olivine,
leucite,
and other pyroxenes.
[
]
Occasional specimens have a shiny appearance that give rise to the mineral's name, which is from the Greek augites, meaning "brightness", although ordinary specimens have a dull (dark green, brown or black) luster. It was named by Abraham Gottlob Werner in 1792.[
]
See also
Further reading
-
Deer, W. A., Howie, R. A., and Zussman, J. (1992). An introduction to the rock-forming minerals (2nd ed.). Harlow: Longman
