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Formula: (Ca,Cu,Na,Fe3+,Al)12Fe3+2(AsO4)8(OH,Cl)x.nH2O
Valence: (Ca,Cu2+,Na,Fe3+,Al)12Fe3+2(As5+O4)8(OH,Cl)x.nH2O
Hydrated arsenate, copper- and
ferric iron- bearing mineral
Crystal system: Monoclinic
Specific gravity: 2.93 to 3.11 calculated
Hardness: May be 2 to 3
Streak: White to pale yellow
Colour: Greenish yellow
Luminescence: Not fluorescent
Solubility: Readily soluble without effervescence in 10% hydrochloric acid at room temperature
Environments
Although Barahonaite-(Fe) was approved in 2006, to date (April 2026) it has been reported only from the type locality.
Localities
At the type locality, La Reconquistada claim, Pastrana, Mazarrón, Murcia, Spain, the oxidation minerals occur as
coatings and within closely spaced fractures in weathered siliceous and micaceous host-rocks.
Pharmacosiderite and
jarosite are the most intimately associated with
barahonaite-(Fe) and barahonaite-(Al). Beads of
barahonaite-(Al) from Spain are only locally coalesced into
aggregates of a few beads.
Barahonaite-(Fe) occurs sparingly as isolated, rosette-like beads, up
to about 200 microns across. The mineral forms sparse coatings on fracture surfaces, generally on a substrate of
pharmacosiderite, and coalescences of glittering beads are the norm
rather than the exception. The surface of the beads of
barahonaite-(Fe) and barahonaite-(Al) consists of razor-thin,
tabular, composite crystals whose maximum length is about 20 microns.
The macroscopically distinct difference between barahonaite-(Fe) and
barahonaite-(Al) is that the latter is pale blue and has a white
streak, whereas
barahonaite-(Fe), owing to its much higher Fe content, is greenish
yellow and has a white to pale yellow streak. Both minerals have a vitreous lustre and are brittle, transparent to
translucent, non-fluorescent, and are readily soluble without effervescence in 10% hydrochloric acid at room
temperature.
Grains of barahonaite-(Fe) are 5 to 10 microns in maximum dimension.
Single-crystal portions of barahonaite-(Al) are only ~1 micron
(CM 46.1.205-217).
Barahonaite-(Fe) occurs as a secondary mineral in the
oxidised zone of the sulphide deposit. Associated minerals
include arsenocrandallite,
arsenogoyazite,
conichalcite,
cobaltarthurite,
chlorargyrite, olivenite,
azurite, cornwallite,
pharmacosiderite, jarosite,
zálesíite and lavendulan
(HOM).
Barahonaite-(Fe) from La Reconquistada claim -
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