Pyrolusite

Pyrolusite
Pyrolusite
General
Category	Oxide minerals
Formula; (repeating unit)	MnO2
IMA symbol	Pyl
Strunz classification	4.DB.05
Crystal system	Tetragonal
Crystal class	Ditetragonal dipyramidal (4/mmm) ; H-M symbol: (4/m 2/m 2/m)
Space group	P42/mnm
Identification
Color	Darkish, black to lighter grey, sometimes bluish
Crystal habit	Granular to massive: botryoidal. Crystals rare
Twinning	{031}, {032} may be polysynthetic
Cleavage	Perfect on 110
Fracture	Irregular/Uneven
Tenacity	Brittle
Mohs scale hardness	6–6.5, 2 when massive
Luster	Metallic, dull to earthy
Streak	Black to bluish-black
Specific gravity	4.4–5.06
Refractive index	Opaque
References
Major varieties
Polianite	pseudomorphic after manganite

Pyrolusite is a mineral consisting essentially of manganese dioxide (Mn O₂) and is important as an ore of manganese.^[7] It is a black, amorphous appearing mineral, often with a granular, fibrous, or columnar structure, sometimes forming reniform crusts. It has a metallic luster, a black or bluish-black streak, and readily soils the fingers. The specific gravity is about 4.8. Its name is from the Greek for fire and to wash, in reference to its use as a way to remove tints from glass.^[5]

^ 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.
^ Mineralienatlas
^ Barthelmy, David (2014). "Pyrolusite Mineral Data". Webmineral.com. Retrieved 4 August 2022.
^ Pyrolusite, Mindat.org, retrieved 4 August 2022
^ ^a ^b Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W.; Nichols, Monte C. (2005). "Pyrolusite" (PDF). Handbook of Mineralogy. Mineral Data Publishing. Retrieved 14 March 2022.
^ Polianite, Mindat.org, retrieved 4 August 2022
^ Reidies, Arno H. (2002), "Manganese Compounds", Ullmann's Encyclopedia of Industrial Chemistry, vol. 20, Weinheim: Wiley-VCH, pp. 495–542, doi:10.1002/14356007.a16_123, ISBN 978-3-527-30385-4.

[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.

[2] Mineralienatlas

[Webmin-3] Barthelmy, David (2014). "Pyrolusite Mineral Data". Webmineral.com. Retrieved 4 August 2022.

[Mindat-4] Pyrolusite, Mindat.org, retrieved 4 August 2022

[Handbook-5] Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W.; Nichols, Monte C. (2005). "Pyrolusite" (PDF). Handbook of Mineralogy. Mineral Data Publishing. Retrieved 14 March 2022.

[6] Polianite, Mindat.org, retrieved 4 August 2022

[Ullmann-7] Reidies, Arno H. (2002), "Manganese Compounds", Ullmann's Encyclopedia of Industrial Chemistry, vol. 20, Weinheim: Wiley-VCH, pp. 495–542, doi:10.1002/14356007.a16_123, ISBN 978-3-527-30385-4.

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