New Utah Minerals – Mcalpineite

By Rebecca L. Hylland

Mcalpineite, Cu3TeO6.H2O
Mcalpineite is a copper-tellurium hydrate, Cu3TeO6.H2O, found in the Centennial Eureka mine of the Tintic Mining District in Juab County. However, it was first identified in the McAlpine mine (the type locality), in Tuolumne County, California.

Mcalpineite was named for this California mine. At the Centennial Eureka mine, Mcalpineite was found as a coating in pore spaces in decalcified, brecciated brown-grey limestone boulders located in the mine dump. Mcalpineite was also found as cryptocrystalline nodules lining drusy quartz vugs in these same limestone boulders. Nodule sizes are small, about 1 millimeter in diameter.

At the Centennial Eureka mine, Mcalpineite’s color ranges from olive-green to dark green-black. It has a light-green streak and a adamantine lustre and is physically similar to a mineral called choloalite. Choloalite, however, has a vitreous lustre. Mcalpineite is nonfluorescent under all wavelengths of ultraviolet light and is brittle with an uneven fracture. Hardness and density have not been determined because the specimens of Mcalpineite that have been found are 1mm or less in size.

Roberts, A.C., Ercit, T.S., Criddle, A.J., Jones, G.C., Williams, S.R., Cureton II, F.F., and Martin, C.J., 1994, Mcalpineite, Cu3TeO6.H2O, a new mineral from the McAlpine mine, Tuolumne County, California, and from the Centennial Eureka mine, Juab County, Utah; Mineralogical Magazine, v. 58, no. 3, p. 414-424.

from Survey Notes, v.27, no.3, August 1995