New Utah Minerals: Orthominasragrite & Oswaldpeetersite

By Carl Ege

Orthominasragrite, V4+O(SO4)(H2O)5

Orthominasragrite is a vanadium sulfate found at the North Mesa mine group in the Temple Mountain mining district, Emery County. The mineral is found as rounded aggregates approximately 0.002 mm across. Orthominasragrite is pale blue to bright blue with a pale blue streak. The mineral has a hardness of 1 and a density of 2.00 g/cm3.

Orthominasragrite occurs in a fossilized log in the Shinarump Conglomerate Member of the Triassic Chinle Formation. The mineral is associated with pyrite, sulfur, minasragrite, and undescribed vanadium sulfate. Orthominasragrite is named for its relationship with the mineral minasragrite.

Oswaldpeetersite, (UO2)2CO3(OH)2 · 4H2O

Oswaldpeetersite is a basic uranyl carbonate found at the Jomac uranium mine in San Juan County. The mineral is found as prismatic crystals in radiating groups. Individual crystals are approximately 0.1 mm long and 0.01 mm wide. Oswaldpeetersite is canary yellow and has a pale yellow streak. The mineral has a hardness between 2 and 3 and a density greater than 4.10 g/cm3. Oswaldpeetersite also occurs in the Shinarump Conglomerate in a fossilized log. The mineral is associated with gypsum, cuprite, goethite, antlerite, lepidocrocite, mbobomkulite, hydrombobomkulite, sklodowskite, and two undefined uranium minerals. Oswaldpeetersite is named for Maurice Oswald Peeters, a structural crystallographer and researcher at the University of Leuven, Belgium.

For more information:

 Hawthorne, F.C., Schindler, M., Grice, J.D., and Haynes, P., 2001, Orthominasragrite, V4+O(SO4)(H7O)5, a new mineral species from the Temple Mountain, Emery County, Utah, U.S.A.: The Canadian Mineralogist, v. 39, p. 1325-1331.

Vochten, R., Deliens, M., and Medenbach, O., 2001, Oswaldpeetersite, (UO2)2CO3(OH)2 · 4H2O, a new basic uranyl carbonate mineral from the Jomac uranium mine, San Juan County, Utah, U.S.A.: The Canadian Mineralogist, v. 39, p. 1685-1689.

Survey Notes, v. 35 no. 1, January 2003