Uraninite (Specimen #100215)

Mineral(s): Uraninite, Calcite, Fluorite, Biotite 

Location: Cardiff Uranium Mine, Cardiff Township, Highlands East Township, Haliburton County, Ontario, Canada 

Size: 7.4 x 6.7 x 6.5 cm 

Provenance: Ex. Royal Ontario Museum; ex. David Joyce Minerals 

Description:  A cubic, dark gray uraninite crystal in a carbonatite matrix of white calcite, dark purple fluorite and biotite. The uraninite crystal is a cube with octahedral modifications, is undamaged and is radioactive. The uraninite cube is well formed and sharp on the edges, sits nicely on the specimen matrix and is 7mm on edge. Uraninite crystals are seldom seen for sale. Uraninite cubes were found in veins cutting amphibolite & syenite gneiss and marble.

The deposit was originally explored for fluorite in 1943 by Cardiff Fluorite Mines Limited: exploration for uranium was conducted by Cardiff Uranium Mines Limited from 1953 to 1955. The mineralization extends for about 3 kilometers along the contact of gneiss and marble ("crystalline limestone"). The development at the South Zone consists of two adits, a shaft to a depth of 83.8 meters, and trenches. The mine is closed and rehabilitated – no new specimens will be recovered from this property.