PSILOMELANE
Specimen psi-5
$ 110.00Dims: 5.0" x 3.2" x 3.0" (12.7 x 8.1 x 7.6 cm)
Wt: 1 lb., 12.4 oz. (806 g)
Manganese District, Grant County, New Mexico, U.S.A.
This large hand specimen consists of a dull, pale brown host rock through which extend several layers of compact Psilomelane. There are also a few crusts of the material that coat portions of its surface. Many of the more exposed layers and crusts show considerable damage, but this damage allows one to see their cross-sections and their almost compact, fibrous habit. A few of the crusts that coat the host rock have a sparkly sheen on their outer surfaces that suggest that they are encrusted with tiny crystals, likely made of quartz. The veins and crusts are layered, showing alternate bands of material that have black and metallic gray colors- cross-sections of a few of the thicker veins show patterns that look like plumose or dendritic formations. The host rock appears to be made up partly of a conglomerate of irregularly-sized and shaped rocks in a finely-grained matrix and layers of a gray flint or chert made of alternating bands of pale and darker brown material.