Formula: Fe3+(SO4)(OH).2H2O
Hydrated sulphate containing hydroxyl, orthorhombic paramorph of
butlerite, which is monoclinic. Butlerite
is sometimes epitaxial on parabutlerite. Parabutlerite has been observed as
pseudomorphs after copiapite.
Crystal System: Orthorhombic
Specific gravity: 2.55 measured
Hardness: 2½
Streak: Light yellow
Colour: Pale orange to pale orange-brown; light yellow in transmitted light.
Solubility: Insoluble in cold or hot water; soluble in dilute acids
Environments
Parabutlerite is an uncommon mineral in the oxidised zone of pyritic veins;
it may be formed by alteration of copiapite. Associated minerals include
copiapite, cuprocopiapite,
butlerite, jarosite,
melanterite and fibroferrite
(HOM, Webmin).
Localities
At Santa Elena Mine, Quebrada Alcaparrosa, Calingasta, Calingasta Department, San Juan Province, Argentina, parabutlerite
occurs with butlerite, fibroferrite
and other sulphates
(Dana).
There are two co-type localities, the Alcaparrosa Mine, Cerritos Bayos, and the Chuquicamata Mine, Chuquicamata District,
both at Calama, El Loa Province, Antofagasta, Chile. At Alcaparrosa parabutlerite occurs in a bed about 8 inches
thick above copiapite. It results from the alteration of
copiapite and in part is pseudomorphic
after it. Parabutlerite also occurs with copiapite and
jarosite at Quetena and Chuquicamata. All of the field evidence points to the
conclusion that parabutlerite formed after copiapite
(AM 23.669-760).
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