Angelite (Anhydrite) – Peru

Angelite is a popular trade name for a variety of Anhydrite that is light blue-grey in colour, semi-transparent, fine grained and marketed as gem material. These specimens, along with most angelite, are from Lima, Peru and were collected near the Casapalca Mine at Casapalca, Huarochiri Province, Lima Department, Peru.

The Casapalca mineral deposits were initially mined to a limited extent by the Spaniards in the 1600s. Over the past century, they have served as a significant source of silver, copper, lead, and zinc. However, amidst these metal deposits, the presence of a unique variety of anhydrite known as “angelite” stands out. Surprisingly, “angelite” formation is unrelated to the metal minerals in the area.

Angelite was created when solutions rich in sulphate interacted with calcite in limestone, leading to the formation of massive anhydrite. This anhydrite possesses a striking blue colour due to trace amounts of divalent (ferrous) iron. These anhydrite formations took shape as nodules within altered limestone layers. Interestingly, when the surface of these anhydrite nodules came into contact with chemically neutral groundwater, they underwent rehydration and transformed into gypsum, resulting in a white coating on “angelite” specimens.

These specimens are ideal for both collectors and educational use, available in a range of sizes. They come supplied in a white card tray with an information label.