Cumberlandite

Photographed by Michael P. Klimetz

Iron Mine Hill Quarry

Cumberland

Providence County

RHODE ISLAND

Photographed by Michael P. Klimetz

Iron Mine Hill Quarry

Cumberland

Providence County

RHODE ISLAND

Photographed by Michael P. Klimetz

Iron Mine Hill Quarry

Cumberland

Providence County

RHODE ISLAND

Photographed by Michael P. Klimetz

Iron Mine Hill Quarry

Cumberland

Providence County

RHODE ISLAND

Photographed by Michael P. Klimetz

Iron Mine Hill Quarry

Cumberland

Providence County

RHODE ISLAND

Cumberlandite is a medium-grained, porphyritic dunite to melatroctolite composed of white or greenish platy crystals (originally of labradorite) as much as half an inch long. The matrix is fine grained to medium grained, and in places the platy crystals are aligned, probably as a consequence of molten plastic flow. The rock is very dense and is also noticebly magnetic. Fresh rock consists of magnetite-ilmenite intergrowth, olivine, labradorite, and spinel. Fresh rock is rare, however, as in most cumberlandite the olivine and labradorite have been replaced by serpentine, actinolite, and other alteration products. Cumberlandite is unique to Rhode Island, although a somewhat similar rock has been described at Taberg, Sweden. Although not been radiometrically dated, Rhode Island cumberlandite is considered to be of Late Proterozoic age.