*Uraninite (Pitchblende) & Coffinite - Temple Mountain Mining District, Emery Co., Utah USA

UO_{2     U(SiO4) · nH2O}

Uraninite and coffinite from the Temple Mountain Mining District in Emery County, Utah, are notable for their significance in the region's rich uranium mining history. Uraninite, a primary uranium ore, is typically found as dark black, dense masses with a metallic to submetallic luster. In the Temple Mountain deposits, it often occurs in association with sandstone-hosted uranium-vanadium mineralization, where it is deposited in narrow seams or clusters along fractures. The uranium content in uraninite makes it highly radioactive, and its presence in this district reflects the geochemical conditions that concentrated uranium in the Triassic Chinle Formation. Temple Mountain uraninite specimens are prized among collectors for their historical and geological importance, often preserved alongside associated secondary uranium minerals such as autunite or carnotite.

Coffinite, a uranium silicate mineral, is another prominent radioactive mineral from Temple Mountain. It is typically found as fine-grained, black to brown masses with a dull luster, often intergrown with uraninite or replacing it. Coffinite forms under reducing conditions in sedimentary environments, making the Temple Mountain Mining District an ideal setting for its occurrence. Specimens from this district are significant for their purity and association with vanadium minerals, which highlight the complex ore genesis processes of the region. The interplay of uraninite and coffinite within the district provides valuable insights into uranium ore formation and is a testament to the unique geological history of this part of Utah.

Ex. David P. Wilber Collection. This is an excellent display specimen, and is yet another piece from my personal collection.

Approx specimen size: 120mm x 65mm x 55mm

Approx. specimen activity on an SE International Ranger EXP: 13000 cpm