Achalaite

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

Achalaite
General
Category	Minerals
Formula	(Fe2+,Mn)(Ti,Fe3+,Ta)(Nb,Ta)2O8
IMA symbol	Ahl[1]
Strunz classification	4.D0.
Crystal system	Monoclinic
Unit cell	a = 9.422(4) [Å], b = 11.427(3) [Å] c = 5.120(1) [Å]; β = 90.12°; Z = 4[2]
Identification
Color	Black
Crystal habit	fibrous
Mohs scale hardness	5.5
Luster	metallic
Streak	black
Specific gravity	6.285
Density	6.285 g/cm3
Pleochroism	Non-pleochroic
References	[2]

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.^[4] Associated minerals include rutile, quartz and albite.^[2]

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.^[2]