Achalaite Explained

Achalaite
Formula:	(Fe^2+,Mn)(Ti,Fe^3+,Ta)(Nb,Ta)2O8
Imasymbol:	Ahl^[1]
Strunz:	4.D0.
System:	Monoclinic
Unit Cell:	a = 9.422(4) [Å], b = 11.427(3) [Å] c = 5.120(1) [Å]; β = 90.12°; Z = 4
Color:	Black
Habit:	fibrous
Mohs:	5.5
Luster:	metallic
Streak:	black
Gravity:	6.285
Density:	6.285 g/cm^3
Pleochroism:	Non-pleochroic
References:	^[2]

Achalaite ((Fe²⁺, Mn)(Ti, Fe³⁺, Ta)(Nb, Ta)₂O₈) is a black mineral of the wodginite group, first discovered in 2013.^[3]

It crystallizes in the monoclinic system and has a dark, metallic luster, a specific gravity of 6.285 and a Mohs hardness of 5.5.^[4]

Achalaite occurs in the intermediate zone of topaz- and tantalite-bearing pegmatite. Associated minerals include rutile, quartz and albite.

Its name comes from the type locality: the Achala batholith in Córdoba, Argentina and the mineral has been approved by the IMA with the acronym 2013-103.

Notes and References

1. Warr. L.N.. 2021. IMA–CNMNC approved mineral symbols. Mineralogical Magazine. 85. 3. 291–320. 10.1180/mgm.2021.43. 2021MinM...85..291W. 235729616. free.
2. Web site: Achalaite . Mindat.org . 8 March 2019.
3. Web site: The New IMA List of Minerals – A Work in Progress – Updated: July 2016 . International Mineralogical Association COMMISSION ON NEW MINERALS, NOMENCLATURE AND CLASSIFICATION . 8 March 2019 . https://web.archive.org/web/20160909231852/http://nrmima.nrm.se/IMA_Master_List_(2016-07).pdf . 9 September 2016 . dead .
4. Web site: Achalaite Fe2+TiNb2O8 . Handbook of Mineralogy . 8 March 2019.