Plagioclase
A continuous solid solution series of feldspar minerals.
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Within the feldspar group, plagioclase constitutes a series of tectosilicate minerals.[1] Earth's crust contains this mineral group more abundantly than any other.[2] Albite (sodium feldspar) and anorthite (calcium feldspar) are the two end members that form a solid solution in this series.[2]
Key facts and history
The Mohs hardness of all plagioclase species is 6 to 6.5.[3] The name comes from Ancient Greek plágios ('oblique') + klásis ('fracture').[3] August Breithaupt gave plagioclase its name in 1847.[4] Petrologists use plagioclase, a major component of Earth's crust, as a key diagnostic tool.[5]
Lunar highland rock also contains plagioclase as a major constituent.[5] On cleavage is perfect, on it is good, and these planes intersect at 93–94°.[3] Polysynthetic twinning, which creates striations on, is nearly always present in plagioclase.[6] Alkali feldspar can be told apart from plagioclase thanks to these striations.[6]
A white to greyish-white color is typical for plagioclase.[7]
What the research sources say
Ferric iron (Fe³⁺) in the tetrahedral site of plagioclase from Lake County, Oregon, produces a pale yellow color.[8]
References
- Wikipedia, "Plagioclase" (CC BY-SA 4.0) en.wikipedia.org
- Wikipedia, "Plagioclase" (CC BY-SA 4.0), which cites: Nesse, "Introduction to mineralogy", Oxford University Press, 2000, p. 219; Klein, "Manual of mineralogy: (after James D. Dana)", Wiley, 1993, p. 543 (we also read that source) en.wikipedia.org
- Wikipedia, "Plagioclase" (CC BY-SA 4.0), which cites: Allaby, "A dictionary of geology and earth sciences", Oxford University Press, 2013; Nesse 2000, p. 208-209; Nesse 2000, p. 208-209 (we also read that source) en.wikipedia.org
- Wikipedia, "Plagioclase" (CC BY-SA 4.0), which cites: "Glossary of geology.", American Geological Institute, 1997; Nesse 2000, p. 208-209 (original not read by us) en.wikipedia.org
- Wikipedia, "Plagioclase" (CC BY-SA 4.0), which cites: Milam, "Distribution and variation of plagioclase compositions on Mars", Journal of Geophysical Research: Planets, 2010 (original not read by us) en.wikipedia.org
- Wikipedia, "Plagioclase" (CC BY-SA 4.0), which cites: Klein Hurlbut 1993, p. 542 (original not read by us) en.wikipedia.org
- Wikipedia, "Plagioclase" (CC BY-SA 4.0), which cites: Allaby, "A dictionary of geology and earth sciences", Oxford University Press, 2013; Klein Hurlbut 1993, p. 542; "Minerals Colored by Metal Ions", minerals.gps.caltech.edu; Klein Hurlbut 1993, p. 542; Nesse 2000, p. 208-209 (we also read that source) en.wikipedia.org
- "Minerals Colored by Metal Ions", minerals.gps.caltech.edu. facts only, no text reused. minerals.gps.caltech.edu
Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Plagioclase (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.
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Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Plagioclase (CC BY-SA 4.0).
- Word definitions: the , each quoted from its Wikipedia article.
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