Esseneite
{{Infobox mineral
| name = Esseneite
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| image = Dorrite & Esseneite.jpg
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| caption = Reddish-brown dorrite crystals associated to orange essenite, and also spinel and magnesioferrite. From: Chelyabinsk, Chelyabinsk Oblast, Russian Federation
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| formula = CaFeAlSiO6
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| class = Monoclinic – prismatic
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| color = Reddish brown
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| cleavage = 110 – Perfect
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| luster = Vitreous (glassy)
| streak = White
| diaphaneity = Transparent
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| density = 3.54
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Esseneite is a relative rare mineral of the pyroxene group, with formula CaFeAlSiO6. It is the ferric-iron-dominant member. Esseneite is an iron-analogue of other pyroxene-group members, davisite, grossmanite, and kushiroite. It is a metamorphic mineral forming in pyrometamorphic rocks called paralavas, which are formed due to fusing on sedimentary rocks usually in result of coal fires. Esseneite is found in both natural and anthropogenic coal-fire sites.[http://www.minsocam.org/ammin/AM72/AM72_148.pdf Michael A. Cosca, Donald R. Peacor, "Crystal structure of esseneite (CaFe3+AlSiO6), a new pyroxene produced by pyrometamorphism." American Mineralogist 72, 148–156 (1987)]{{cite web|url=http://www.mindat.org/min-1413.html |title=Esseneite: Esseneite mineral information and data |website=Mindat.org |accessdate=2016-03-02}}
Esseneite was named for Eric J. Essene (1939–2011), a metamorphic petrologist and Professor of Geosciences at the University of Michigan.
The mineral crystallizes in the monoclinic crystal system with space group C2/c.