Angelite outcrops, Casapalca Mine, Casapalca, Chicla District, Huarochirí Province, Lima, Perui

Regional Level Types
Angelite outcrops	Outcrop
Casapalca Mine	Mine
Casapalca	Town
Chicla District	District
Huarochirí Province	Province
Lima	Region
Peru	Country

All of "angelite" specimens from Lima are/were collected near the Casapalca Mine at Casapalca, Huarochiri Province, Lima Department, Peru. Peruvian "angelite" also occurs in the adjacent Morococha district in Yauli Province, Junin Department (exact location unknown). Blue anhydrite from these sources is the only material to which the variety name “angelite” should be applied. Forms of anhydrite with much paler bluish hues are found in Mexico, Germany, and the United States.

The Casapalca mineral deposits are believed to have been first mined to a limited extent by the Spaniards in the 1600s; in modern times, they have been a significant source of silver, copper, lead, and zinc for more than a century. The occurrence of the "angelite" variety of anhydrite, however, is not related to metal mineralization. Instead, angelite formed when sulfate rich solutions converted the calcite in limestone to massive anhydrite with a distinctive blue color that is caused by trace amounts of divalent (ferrous) iron. This anhydrite formed nodules within a layer of altered limestone. When the surface of these anhydrite nodules later contacted chemically neutral groundwater, it rehydrated into gypsum, which appears as a white coating on "angelite" specimens. "Angelite" is collected today by Casapalca metal miners and sold to dealers and gem cutters as a source of secondary income [1].

Other Regions, Features and Areas containing this locality

References