Carrollite

It's advisable to handle carrollite carefully to avoid generating dust and wash hands thoroughly afterward. When cutting or polishing carrollite, wear a dust mask to prevent inhaling heavy metal particles. Store carrollite in a sealed container in a well-ventilated area, away from children and pets. For those involved in crystal healing, never put it in your mouth.

Carrollite can be used as a cobalt ore. Its crystals have a bright, silvery, metallic color and finish which rarely tarnishes, which makes them attractive to, and fairly popular with, mineral collectors.

Carrollite is found worldwide; reported in Australia, Austria, Azerbaijan, Brazil, Bulgaria, Canada, Chile, China, the Czech Republic, the Democratic Republic of Congo, France, Germany, Japan, Morocco, Namibia, North Korea, Norway, Oman, Poland, Romania, Russia, Slovakia, Sweden, Switzerland, US and Zambia.

Carrollite occurs in hydrothermal vein deposits associated with tetrahedrite, chalcopyrite, bornite, digenite, djurleite, chalcocite, pyrrhotite, pyrite, sphalerite, millerite, gersdorffite, ullmannite, cobaltoan calcite, and with linnaeite group members linnaeite, siegenite and polydymite.

Phase relations in the Cu-Co-S system have been investigated. At temperatures around 900 °C a chalcocite-digenite solid solution coexists with cobalt sulfides. With decreasing temperature, at 880 °C a carrollite-linnaeite solid solution develops, becoming more copper-rich on cooling, with the carrollite composition at about 500 °C. Below 507 °C covellite is stable and coexists with copper-bearing cattierite. Low chalcocite appears at 103 °C, djurleite appears at 93 °C, and digenite disappears and anilite appears around 70 °C. There is some evidence for supergene replacement of an intermediate member of the linnaeite-carrollite series by djurleite.