Tritomite-(Y) [Spencite] — Cardiff Uranium Mine, Cardiff Township, Haliburton County, Ontario

A scarce rare-earth borosilicate with a genuinely interesting naming history, from one of the classic Bancroft-area uranium properties. The Cardiff Uranium Mine — originally explored for fluorite in 1943 before uranium development began in the 1950s — worked veins cutting amphibolite and syenite gneiss, producing a diverse radioactive and rare-earth mineral suite that includes chondrodite, allanite, uraninite, and this specimen's species.

This piece is labeled as both tritomite and spencite — and there's a reason for that pairing. Spencite was originally described as its own species in 1961, named for Hugh S. Spence, the Canadian mineralogist who first discovered the mineral back in 1934. It was recognized as the yttrium-dominant analogue of tritomite-(Ce), a related cerium-dominant borosilicate first described from Norway decades earlier. When rare-earth mineral nomenclature was revised in the 1960s–80s, spencite was folded into tritomite-(Y) as a synonym — tritomite having priority as the earlier name — but "spencite" remains in long-standing use among Canadian collectors and on older specimen labels, making dual-labeled pieces like this one a nice piece of mineralogical history in their own right.

Tritomite-(Y) belongs to the britholite group within the apatite supergroup, with rare-earth elements substituting strongly for calcium — and, consistent with its Cardiff-area origin, it carries associated radioactivity from contained thorium and uranium.

Approx. specimen size: 130mm x 70mm x 13mm

Approx. specimen weight: 296.39g

Species: Tritomite-(Y) [syn. Spencite]
Locality: Cardiff Uranium Mine, Cardiff Township, Highlands East Township, Haliburton County, Ontario, Canada
Radioactivity: Present — handle and store per standard radioactive mineral practice
Approx. activity: 30000 CPM

Radioactive Mineral Shipping Policy

All naturally radioactive mineral specimens are available for shipping within Canada only. Due to Transport Canada dangerous goods regulations and Canadian Nuclear Safety Commission requirements, we cannot ship radioactive materials internationally. All specimens are packaged in accordance with excepted quantity guidelines and clearly labeled. Purchasers are responsible for ensuring they are legally permitted to possess radioactive mineral specimens under applicable provincial and federal regulations. If you have questions about a specific specimen's activity level or shipping eligibility, please contact us before purchasing.