Uraninite Crystal - Cardiff Uranium Mine, Cardiff Township, Hastings County, Ontario, Canada

UO₂

A great example of a  Uraninite crystal from the Cardiff Uranium Mine, Cardiff Township, Hastings County, Ontario, Canada. These specimens are becoming increasingly difficult to find on the collectors market as the source has long since been closed down, and most of what is available has disappeared into private collections.

Cardiff Uranium Mine 

URANINITE, FLUORITE, CALCITE, APATITE, PHLOGOPITE, PYROXENE, SCAPOLITE, MOLYBDENITE; NORBERGITE, FLUOBORITE, SEPIOLITE, TOURMALINE, SERPENTINE, TITANITE, TALC, GRAPHITE, PYRITE, PYRRHOTITE

In veins cutting amphibolite and syenite gneiss; in crystalline limestone This deposit was formerly explored for uraninite and fluorite. These minerals occur in calcite veins. Uraninite cubes measuring 5 mm to 2.5 cm have been reported. Fluorite is purple to almost black and commonly forms bands in cream-white to pink calcite that fluoresces pink under "short" ultraviolet rays. Green apatite crystals measuring up to 5 cm in diameter and mica books, 7 to 10 cm in diameter were reported from the deposit. Green pyroxene, scapolite, titanite, molybdenite and "micro" quartz crystals also occur in the calcite.

Dolomitic crystalline limestone associated with the deposit contains: orange norbergite commonly forming bands in the limestone, pink fluoborite crystals (about 5 mm long), white fibrous sepiolite forming patchy encrustations on the limestone, pink tourmaline grains, green serpentine, brownish pink titanite grains, amber mica, colourless to grey prismatic aggregates of clinoamphibole, blue apatite grains, white to light blue fibrous talc, light green prismatic clinopyroxene, graphite, pyrite and pyrrhotite.

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 km along the contact of gneiss and crystalline limestone. The development at the South zone consists of two adits, a shaft to a depth of 83.8 m and trenches. The openings are on the eastern slope of a ridge overlooking Irondale River. There is a large dump adjacent to the shaft. The property is held by Rare Earth Resources Limited.

Citation

Sabina, A. P. (1986). Rocks and minerals for the collector: Bancroft - Parry Sound area and southern Ontario. Geological Survey of Canada, Miscellaneous Report, 39, 182. https://doi.org/10.4095/121046

Approx. specimen size: 17mm x 17mm x 14mm

Approx. specimen activity on an SE International Ranger EXP: 90 000 cpm