Babingtonite

Babingtonite
Babingtonite
General
Category	Inosilicate
Formula; (repeating unit)	Ca2(Fe,Mn)FeSi5O14(OH)
IMA symbol	Bab
Strunz classification	9.DK.05
Crystal system	Triclinic
Crystal class	Pinacoidal (1) ; (same H-M symbol)
Space group	P1
Identification
Color	Dark green to black
Crystal habit	Prismatic crystals
Cleavage	Perfect on {001}, Good on {010} and {100}
Fracture	Irregular/uneven
Tenacity	Brittle
Mohs scale hardness	5.5 to 6
Luster	Vitreous
Diaphaneity	Translucent on thin edges, opaque
Specific gravity	3.3
Refractive index	nα= 1.700 nβ= 1.710 nγ= 1.725
Birefringence	δ = 0.025
Pleochroism	Visible
Dispersion	r > v strong
References

Babingtonite is a calcium iron manganese inosilicate mineral with the formula Ca₂(Fe,Mn)FeSi₅O₁₄(OH). It is unusual in that iron(III) completely replaces the aluminium so typical of silicate minerals. It is a very dark green to black translucent (in thin crystals or splinters) mineral crystallizing in the triclinic system with typically radial short prismatic clusters and druzy coatings. It occurs with zeolite minerals in cavities in volcanic rocks. Babingtonite contains both iron(II) and iron(III) and shows weak magnetism. It has a Mohs hardness of 5.5 to 6 and a specific gravity of 3.3.

It was first described in 1824 from samples from Arendal, Aust-Agder, Norway (which is its type locality) and was named after the Irish physician and mineralogist William Babington (1757–1833).^[3]^[4]

It is the official mineral (mineral emblem) of the Commonwealth of Massachusetts.^[5] The first published report of babingtonite in Massachusetts was by Francis Alger in 1844,^[6] who credited Thomas Nuttall with its discovery in Charlestown (now Somerville). The location was the Granite Street quarry, formerly known as the Milk Row quarry.^[7]

Gallery

Jet black babingtonite from Lane Quarry, Northfield, Franklin County, Massachusetts, US
Triclinic crystals of babingtonite with prehnite, from Qiaojia, Qiaojia Co., Zhaotong, Yunnan, China
Black babingtonite which covers a matrix of botryoidal, green prehnite, and a large, colorless, doubly terminated quartz crystal
Babingtonite (dark) on prehnite, Qiaojia, Qiaojia County, Yunnan Province, China

References

^ 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.
^ "Babingtonite". www.mindat.org. Retrieved 12 October 2022.
^ "Babingtonite Mineral Data". webmineral.com. Retrieved 12 October 2022.
^ "William Babington - Hektoen International".
^ Massachusetts: Mineral or mineral emblem of commonwealth The first published report of babingtonite in Massachusetts was by Francis Alger in 1844
^ Phillips, W., Allan, R., and Alger, F. (1844) An Elementary Treatise on Mineralogy, 5th ed. (Boston: W. D. Ticknor & Co.)
^ Cristofono, Peter (January 19, 2019). "The Granite Street Quarry, Somerville, Massachusetts: Its History and Minerals".

External links

Mineral galleries

[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.

[Mindat-2] "Babingtonite". www.mindat.org. Retrieved 12 October 2022.

[3] "Babingtonite Mineral Data". webmineral.com. Retrieved 12 October 2022.

[4] "William Babington - Hektoen International".

[5] Massachusetts: Mineral or mineral emblem of commonwealth The first published report of babingtonite in Massachusetts was by Francis Alger in 1844

[6] Phillips, W., Allan, R., and Alger, F. (1844) An Elementary Treatise on Mineralogy, 5th ed. (Boston: W. D. Ticknor & Co.)

[7] Cristofono, Peter (January 19, 2019). "The Granite Street Quarry, Somerville, Massachusetts: Its History and Minerals".

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