Dims: 2.13x0.55x0.24" (5.4x1.4x0.6cm)
Wt: 22.6ct (4.52g)
Rayas Mine, Guanajuato, Mexico
This is an excellent specimen of acanthite. It is a pseudomorph (after argentite), showing several crystal forms characteristic of that mineral, including distorted cubes and dodecahedrons. The specimen has an intricate crystal form, as it is a long crystal with many small crystals attached - I would not call it arborescent, because none of the "branches" are long, the longest is about 3mm in length. The acanthite is the usual metalic silver in color, opaque, and with a metallic luster. Apart from the base, it is undamaged. THere is a small amount of a slightly pink mineral on the base. I am not sure of its composition, but it looks like a low grade (massive) rhodochrosite.