Parabutlerite

minerals

butlerite

copiapite

jarosite

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.
Specific gravity: 2.55
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

Hydrothermal 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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