Uraninite & Erythrite — Eldorado Mine, Port Radium, Northwest Territories

Few addresses in North American mining history carry the weight of Port Radium. The Eldorado Mine — also known as Port Radium — operated across several working periods between 1932 and 1982, producing radium, uranium, and silver from a deposit on the east arm of Great Bear Lake in the Northwest Territories. It was discovered on May 16, 1930, by prospector Gilbert LaBine, who identified high-grade pitchblende and silver at the site and established what would become one of Canada's most strategically consequential ore bodies. The mine supplied radium for medical use in its first decade, then pivoted to uranium production during the Second World War — ore from Eldorado fed the Manhattan Project, and the operation was quietly nationalized by the Canadian government in 1943–44 to secure the supply. Uranium continued to be produced here through the Cold War era, and the site operated under successive ownership until final closure in 1982. The geological setting is one of the most extensive examples of a five-element vein deposit type, with the principal ore stage defined by the co-occurrence of uranium, silver, cobalt, nickel, and arsenic. It is precisely this Co-Ni-As chemistry that gives this combination specimen its character. The primary uraninite — dense, sooty, and strongly radioactive — occurs alongside erythrite, the secondary cobalt arsenate that develops vivid crimson-pink to deep violet-red blooms on weathered cobalt arsenide surfaces in the oxidation zone. Erythrite is a hydrated cobalt arsenate (Co₃(AsO₄)₂·8H₂O) known historically as "cobalt bloom," used by prospectors as a surface indicator of cobalt and native silver ore beneath. Its colour ranges from deep magenta to pale rose depending on cobalt concentration and crystal habit, and fine examples are sought after both as standalone collector minerals and as indicators of a richer mineral association. The contrast of jet-black uraninite against the crimson erythrite is visually striking and scientifically meaningful: it documents both the primary ore mineralogy and the oxidation-zone secondary chemistry of this iconic Canadian locality in a single hand specimen. Port Radium material circulates rarely in the collector market. Offered with full locality documentation. Strongly radioactive. Canada domestic shipping only. Approx. specimen size: 50mm x 40mm x 30mm Approx. specimen weight: 84.33 grams Approx. specimen activity on an SE International Ranger EXP: 22000 CPM