Dims: 2.70x1.69x0.94" (6.86x4.30x2.40cm)
Wt: 2.77oz (78.3g)
Monument #1 Mine, Navajo County, Arizona, USA
This rock is host to two distinct minerals. The yellow mineral on one face is volborthite in fuzzy yellow masses or tiny intergrown blades (remeniscent of barite rosettes). The flat blades have a pearly luster, and a slightly green tint to their yellow color. The other mineral is distinctly green, more massive in appearance (with little indication of crystals), and occurs in patches on all sides of the specimen. I believe this mineral is calciovolborthite, although it is difficult to be certain when crystals are not visible.