Pyroxferroite

Pyroxferroite
Pyroxferroite
	Pyroxferroite
General
Category	Inosilicate
Formula; (repeating unit)	(Fe2+,Ca)SiO3
IMA symbol	Pxf
Strunz classification	9.DO.05
Crystal system	Triclinic
Space group	P1 (no. 2)
Unit cell	a = 6.6213 Å, ; b = 7.5506 Å, ; c = 17.3806 Å, ; α = 114.267°, β = 82.684°, γ = 94.756°, Z = 14
Identification
Color	Yellow
Cleavage	Good on (010), poor on (001)
Mohs scale hardness	4.5–5.5
Luster	Vitreous
Streak	White
Specific gravity	3.68–3.76 g/cm3 (measured)
Optical properties	Biaxial (+)
Refractive index	nα = 1.748–1.756 ; nβ = 1.750–1.758 ; nγ = 1.767–1.768
Pleochroism	Faint; pale yellow to yellow-orange
2V angle	34–40°
References

Pyroxferroite (Fe²⁺,Ca)SiO₃ is a single chain inosilicate. It is mostly composed of iron, silicon and oxygen, with smaller fractions of calcium and several other metals.^[2] Together with armalcolite and tranquillityite, it is one of the three minerals which were discovered on the Moon during the 1969 Apollo 11 mission. It was then found in Lunar and Martian meteorites as well as a mineral in the Earth's crust. Pyroxferroite can also be produced by annealing synthetic clinopyroxene at high pressures and temperatures. The mineral is metastable and gradually decomposes at ambient conditions, but this process can take billions of years.

^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
^ ^a ^b "Pyroxferroite" (PDF). Handbook of Mineralogy. Retrieved 2009-08-07.
^ "Pyroxferroite". Mindat.org. Retrieved 2010-08-07.
^ "Pyroxferroite". Webmineral. Retrieved 2010-08-07.
^ Chao, E. C. T.; et al. (1970). "Pyrox-ferrite, a new calcium-bearing iron silicate from Tranquillity Base". Geochimica et Cosmochimica Acta Supplement. 1: 65. Bibcode:1970GeCAS...1...65C.
^ Windley, B.F. (1973). "Proceedings of the Second Lunar Science Conference". Journal of Geology. 81 (4): 523–524. Bibcode:1973JG.....81..523W. doi:10.1086/627901.

[1] Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.

[handbook-2] "Pyroxferroite" (PDF). Handbook of Mineralogy. Retrieved 2009-08-07.

[mindat-3] "Pyroxferroite". Mindat.org. Retrieved 2010-08-07.

[webmin-4] "Pyroxferroite". Webmineral. Retrieved 2010-08-07.

[j3-5] Chao, E. C. T.; et al. (1970). "Pyrox-ferrite, a new calcium-bearing iron silicate from Tranquillity Base". Geochimica et Cosmochimica Acta Supplement. 1: 65. Bibcode:1970GeCAS...1...65C.

[6] Windley, B.F. (1973). "Proceedings of the Second Lunar Science Conference". Journal of Geology. 81 (4): 523–524. Bibcode:1973JG.....81..523W. doi:10.1086/627901.

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