Fergusonite-(Y) — J.G. Gole Quarry, Murchison Township, Nipissing District, Ontario

A genuinely scarce Ontario radioactive mineral. Fergusonite-(Y), an yttrium-niobium-tantalum oxide, occurs only sparingly at the J.G. Gole Quarry — one of the classic granite pegmatite localities of the Grenville Province, where a rare-earth-rich dyke of white-to-grey plagioclase and glassy quartz has produced an unusually diverse rare-earth mineral suite, including fergusonite-(Y), euxenite-(Y), samarskite-(Y), and hellandite-(Y).

At this locality, fergusonite-(Y) forms as well-formed dipyramidal crystals, typically small — a crystal reaching 2 cm is considered an excellent find — with a dark brown to black, submetallic to resinous surface. Like most Y-group niobates, its crystal structure has been partially disordered by long-term self-irradiation from contained uranium and thorium, giving fine specimens a distinctive semi-vitreous, glassy character. This is genuine, well-formed Gole Quarry material representing one of the rarer species collectors can obtain from this historic Bancroft-area pegmatite.

Species: Fergusonite-(Y), YNbO₄
Locality: J.G. Gole Quarry, Murchison Township, Nipissing District, Ontario
Radioactivity: Present — handle and store per standard radioactive mineral practice
Approx. activity: