Daubréelite

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Daubréelite
Harvard Museum of Natural History. Meteor from Coahuila (DerHexer) 2012-07-20.jpg
Coahuila meteorite fragment ("type locality"), Mineralogical Museum, Natural History Museum, Harvard University
General
CategorySulfide mineral
Formula
(repeating unit)
Fe2+Cr3+2S4
Strunz classification2.DA.05
Dana classification02.10.01.11
Crystal systemCubic
Crystal classHexoctahedral (m3m)
H-M symbol: (4/m 3 2/m)
Space groupFd3m
Unit cella = 9.966 Å; Z = 8
Identification
ColorBlack
Crystal habitMassive, platy aggregates, exsolution lamellae in troilite
CleavageDistinct
FractureUneven
TenacityBrittle
Mohs scale hardness4.5-5
LusterMetallic
StreakBrown or black
DiaphaneityOpaque
References[1][2][3]

Daubréelite is a rare sulfide mineral. It crystallizes with cubic symmetry and has chemical composition of Fe2+Cr3+2S4. It usually occurs as black platy aggregates.[4]

Naming and history[edit]

Daubréelite was named after the French mineralogist, petrologist and meteoriticist Gabriel Auguste Daubrée. The mineral was first described in 1876 in the American Journal of Science. Its type locality is the Coahuila meteorite, Bolsom de Mapimí, Coahuila, Mexico.

Classification[edit]

In the Nickel-Strunz classification daubréelite is part of the "Sulfides and Sulfosalts" and further a "metal sulfide with a metal-sulfide ratio of 3:4 and 2:3".[4]

Occurrences[edit]

Daubréelite is found in iron meteorites as an inclusion in meteoric iron (kamacite and taenite). Further paragenetic minerals are alabandine, enstatite, graphite, plagioclase and schreibersite.[3]

According to one source daubréelite has been described from 34 localities.[1] Some notable examples being the ALH 84001 meteorite, Hoba meteorite, and the Canyon Diablo meteorite.

The mineral was also found in the Hadley Rille meteorite which was retrieved by the Apollo 15 mission in the Rima Hadley (Mare Imbrium).[5]

Crystallography[edit]

Daubréelite crystallizes with cubic symmetry with the space group Fd3m (4/m 3 2/m). There are 8 formula units in one primitive cell.[4]

See also[edit]

References[edit]

  1. ^ a b "Daubréelite Mindat". Mindat. Retrieved 19 December 2012.
  2. ^ Daubréelite data on Webmineral
  3. ^ a b Daubréelite on the Handbook of Mineralogy
  4. ^ a b c Strunz, Hugo; Nickel, Ernest H. (2001). Strunz mineralogical tables : chemical-structural mineral classification system (9 ed.). Stuttgart: Schweizerbart. ISBN 3-510-65188-X.
  5. ^ "Hadley Rille". Meteoritical Society. Retrieved 19 December 2012.