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Formula: KFe3+(SO4)2
Anhydrous sulphate, yavapaiite group
Crystal System: Monoclinic
Specific gravity: 2.88 measured, 2.891 calculated
Hardness: 2½ to 3
Streak: White to pale yellow
Colour: Pale purplish pink
Solubility: Soluble in water with separation of Fe(OH)3 from weakly acid solution
Environments
Localities
At the type locality, the United Verde Mine, Jerome, Verde Mining District, Black Hills, Yavapai County, Arizona,
USA, yavapaiite is of very limited occurrence; it formed a cement in rubble in the open pit operations of the
mine, that is now closed and all traces of the occurrence are lost. The specimen studied consisted of an irregularly
shaped fragment, 20 x 25 mm in size, with saccharoidal texture. Yavapaiite makes up 90% to 95% of the specimen,
forming equidimensional grains about 0.2 mm across, although occasionally, in vugs, short, stumpy crystals may reach
0.6 mm in length. The mineral formed upon coarsely crystalline voltaite, and
is dusted with minor quantities of sulphur,
jarosite, and other unidentified sulphates;
alunite may be present but its occurrence has not been definitely proved.
Crystals of yavapaiite are perfectly transparent, with a vitreous lustre that is almost adamantine in some
instances, and very pale pink colour with a slight purple hue. The streak is white but the colour of finely powdered
material is very pale yellow; it is perfectly colourless in transmitted
light
(AM 44.1105-1114).
This mine was the site of a sulphide ore mine fire that started in 1894 and burned for several years, forming a suite
of new species
(Mindat).
Yavapaiite from the United Verde Mine -
Image
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