Euxenite-(Y) (labeled "Lyndochite") — Beryl Pit, Quadeville, Lyndoch Township, Renfrew County, Ontario

This specimen carries one of the more interesting nomenclature stories in Canadian mineralogy. The label reads "Lyndochite" — and that name has a legitimate history at this exact locality. In 1927, H.V. Ellsworth of the Geological Survey of Canada described a mineral from a pegmatite dike in Lyndoch Township as a new species of the euxenite-polycrase group, naming it lyndochite after the township. The pegmatite occurrence had first been noted by geologist Willet G. Miller in 1897, who observed a shining black mineral in the feldspar with conchoidal fracture and a vitreous lustre he tentatively assigned to the columbate group. Ellsworth's 1927 formal description elevated it to species status and anchored the locality — today known as the Beryl Pit or Quadeville Beryl Mine — as the type locality for lyndochite. The story continued to evolve. A 2002 reinvestigation of the type material by T.S. Ercit, published in The Canadian Mineralogist, found that the lyndochite originally described by Ellsworth is properly a thorium-rich variety of euxenite-(Y), not a distinct species — and that what had been circulating under the "lyndochite" name from a later analytical study was actually aeschynite-(Y). The IMA subsequently discredited lyndochite as a separate mineral. What Ellsworth collected and described from this pegmatite — and what collectable specimens from the Beryl Pit have consistently yielded — is euxenite-(Y), a yttrium niobate-titanate of the formula (Y,Ca,Ce,U,Th)(Nb,Ta,Ti)₂O₆. Euxenite-(Y) is a complex rare earth oxide mineral that earns its name from the Greek for "hospitable to strangers" — a reference to its capacity to accommodate a wide range of otherwise incompatible elements including yttrium, uranium, thorium, cerium, niobium, tantalum, and titanium within a single structure. At the Beryl Pit it occurs as dark brownish-black to submetallic crystals and masses embedded in pegmatitic feldspar, frequently surrounded by a halo of radiation-damaged host mineral. The uranium and thorium content makes these specimens genuinely radioactive. The Beryl Pit remains a visited and productive collector locality today, and euhedral crystals of euxenite-(Y) are still obtained there, making it one of Ontario's premier rare earth mineral localities. This specimen retains its original "Lyndochite" label — making it a piece of nomenclature history in its own right, documenting the old identification before the mineral was formally reassigned. This specimen shows signs of repair from the original collector. Radioactive. Canada domestic shipping only. Approx. specimen size: 135mm x 25mm x 20mm Approx. specimen weight: 153.14 grams Approx. specimen activity on an SE International Ranger EXP: 10000 CPM