Yavapaiite

yavapaiite

voltaite

jarosite

sulphur

Images

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

Fire zones
Fumeroles

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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