Akrochordite is not alone in having Långban as its type locality; incredibly it shares that distinction with
over 70 other minerals, and the total number of different mineral species found here is a staggering 300 plus.
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Formula: Mn2+5(AsO4)2(OH)4.4H2O
Hydrated arsenate containing hydroxyl,
akrochordite group,
manganese-bearing mineral
Crystal System: Monoclinic
Specific gravity: 3.194 to 3.35 measured, 3.26 calculated
Hardness: 3½
Colour: Yellowish red-brown, pale to dark brown, pale pink
Solubility: Readily soluble in dilute sulphuric acid, yielding a lilac-coloured solution
(Mindat).
Environments:
Akrochordite is a rare arsenate, commonly associated with
chlorophoenicite and
sarkinite
(Mindat).
It usually crystallises latest in the sequence of other arsenates
(AM74.256-262).
At the type locality, Långban, Värmland, Sweden, akrochordite occurs in
hausmannite ore from a metamorphosed
iron - manganese orebody,
associated with pyrochroite,
hausmannite, eveite,
dolomite, brandtite and
baryte
(Mindat, Wembin, HOM, Dana).
At Sterline Hill, New Jersey, USA, akrochordite occurs in a metamorphosed stratiform
zinc
orebody, associated with
sarkinite,
chlorophoenicite and carbonates
(HOM, Webmin)
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