Black Rock district—Monte Cristo mine

Region West, Southwest
Mineral systems
Deposit types
Other minerals

Information leading to the delineation of this focus area

Basis for focus area Focus area around Monte Cristo mine in the Constellation area of the Black Rock mining district in Yavapai County, Arizona.
Identified resources Historical production of native silver.
Production Unknown.
Status Past mining.
Estimated resources Unknown.
Geologic maps Arizona Bureau of Mines (1958), scale 1:375,000.
Geophysical data Inadequate Rank 4 aeromagnetic coverage.
Favorable rocks and structures High-angle quartz veins, associated with rhyolite or andesite dikes of probable Mid-Tertiary age, that cut Precambrian granitic gneiss.
Deposits Monte Cristo mine (MRDS dep_id: 10027541).
Evidence from mineral occurrences MRDS.
Geochemical evidence From Bastin (1922): Silver occurs as the native metal, often with niccolite (nickeline, a Ni-arsenide) and more rarely with chloanthite (a Ni-arsenide isomorphous with skutterudite). Two generations of ores include: 1) arsenopyrite, pyrite, chalcopyrite, and quartz, and 2) proustite, tennantite, and calcite, with minor amounts of chalcopyrite, gersdorffite, argentite, pearceite (ruby silver), and quartz.
Geophysical evidence Unknown.
Evidence from other sources Past exploration.
Comments Bastin (1922) stated that the Monte Cristo ores conclusively showed that native Ag occurred as a primary associate of Ni and Co arsenides.
Cover thickness and description Veins exposed at the surface; best silver values at depth.
Authors Laurel G. Woodruff.
New data needs Updated geologic mapping, lidar, geochemistry, aeromagnetic and aeroradiometric surveys.
Geologic mapping and modeling needs Updated geologic mapping.
Geophysical survey and modeling needs High-resolution, Rank 1 aeromagnetic and aeroradiometric surveys.
Digital elevation data needs Lidar inadequate.