VOLBORTHITE
Specimen vol-1

Dims: 2.64x1.66x0.67" (6.71x4.21x1.69cm)

Wt: 1.22oz (34.6g)

Monument Valley, Navajo County, Arizona, USA

This large sliver of rock is essentially covered with volborthite, most of which is a non-crystalline crust in several shades of pale green. Some areas have a fine moss-like appearance, almost velvety under a loupe. The thicker (and more protected areas) appear sparkly and a deeper green, and my loupe reveals that the volborthite in these areas is organized in tiny green rosettes, looking very much like the larger rosettes that barite often forms. This is a very pretty specimen of this rare mineral.

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.