Creaseyite

Formula: Cu2Pb2Fe3+2Si5O17.6H2O
Unclassified silicate
Specific gravity: 4.1
Hardness: 2½
Streak: Pale green
Colour: Yellow-green
Solubility: Decomposed by hot dilute hydrochloric and nitric acid, yielding a silica sponge; fuses to a rusty brown slag.
Environments:

Hydrothermal environments

Creaseyite is found in the oxidised zones of copper deposits.
At Caborca, Sonora, Mexico, creaseyite is mostly replaced by chrysocolla.
At the Gallagher Vanadium property and Manila mine, Cochise county, Arizona, USA, creaseyite is associated with cerussite, and occurs as inclusions in cerussite and calcite.
At Tiger, Gila county, Arizona, USA, creaseyite occurs in the oxidised zone of a base-metal deposit, in andesite breccia loosely cemented with iron oxides and wulfenite, and associated with mimetite, dioptase, fluorite, willemite, wulfenite, descloizite and murdochite.
At the Potter-Cramer property, Maricopa county, Arizona, USA, creaseyite is associated with ajoite and fluorite.
At Wickenburg, Maricopa county, Arizona, USA, creaseyite occurs with fluorite and ajoite.
At the Mammoth mine, Pinal county, Arizona, USA, creaseyite occurs in oxidised zones with wulfenite, willemite and mimetite.

Common impurities: Al,Zn