Dolomite (on tennantite subgroup after enargite)

enargite; tennantite subgroup; tennantite-(Cu) (?); zincolivenite

A plate of sulphide ore hosting free-standing pseudomorphs (to 10 mm) of tennantite subgroup after enargite, richly encrusted with pale pink dolomite which is locally accented by a group of bright green zincolivenite crystals.  The colour of the dolomite is probably due to the presence of trace amounts of cobalt and, while the specimen has not been analysed, the plausibility of tennantite-(Cu) (?) replacing enargite is noted, given the composition of the precursor - Cu₃AsS_{4 .}

The specimen is from the collection of Sharon and Eugene Cisneros.