Thorite from the Kemp Prospect in Cardiff Township, Haliburton County, Ontario, is renowned among mineral collectors for its exceptional crystal quality and rarity. This tetragonal thorium silicate mineral, with the chemical formula ThSiO₄, often occurs in sharp, euhedral crystals exhibiting rust-brown to brick-red hues and a vitreous to resinous luster. Specimens from this locality are notable for their size and form, with some crystals reaching up to 5.2 cm in length. The Kemp Prospect has yielded world-class examples of thorite, including doubly terminated and floater crystals, making it a significant source for this mineral. Additionally, the site has produced uranothorite, a uranium-rich variety of thorite, highlighting the area's complex geochemistry .
Geologically, the Kemp Prospect is situated within the Grenville Province and is characterized by skarn-type lithology. Thorite mineralization here is associated with minerals such as diopside, zircon, scapolite, and pyroxene group minerals, reflecting the high-temperature metamorphic conditions of the region. The thorite specimens often occur in massive forms embedded within the matrix, displaying the classic coloration and radioactive properties typical of thorium-bearing minerals. Due to its significant thorium content—ranging from 50% to 80% by mass—and its radioactivity, handling thorite from this locality requires appropriate safety precautions . The combination of its aesthetic appeal, rarity, and geological significance makes thorite from the Kemp Prospect a prized addition to mineral collections worldwide.
Approx. specimen activity on an SE International Ranger EXP: 10 000 cpm
Approx. specimen size: 60mm x 40mm x 10mm
Th(SiO4)
