Uranopyrochlore — Macdonald Mine, Hastings County, Ontario

Pyrochlore group minerals occupy an important niche in the radioactive mineral world: complex niobate-tantalate oxides with a flexible structure that accommodates uranium, thorium, rare earth elements, and a range of other substitutions. Uranopyrochlore is the uranium-dominant member of the group, characterized by elevated U content at the A-site of the pyrochlore structure. Like other pyrochlore group minerals in uranium-bearing pegmatite systems, uranopyrochlore is frequently metamict — its crystal structure progressively disordered by sustained self-irradiation — and occurs as octahedral to modified cubic crystals, often with a dark brown to black colour and resinous to adamantine lustre.

The Macdonald Mine in Hastings County is a Bancroft camp locality with a history of uranium and associated rare mineral production, situated in the same Grenvillian pegmatite belt responsible for the broader Bancroft uranium district. Uranopyrochlore from this locality is a genuine mineralogical specimen, not a common find: pyrochlore-group minerals are collected both for their own intrinsic interest and as representatives of the broader niobium-uranium mineral suite that characterizes this part of the Canadian Shield. This specimen is offered for advanced radioactive and rare mineral collections.

Radioactive. Canada domestic shipping only.

Approx. specimen size: 90mm x 65mm x 55mm

Approx. specimen weight: 247.55 grams

Approx. specimen activity on an SE International Ranger EXP: 46000 CPM