An extremely, extremely scarce example of millerite from this old silver mining district, where it was always exceedingly rare. I have never seen one before, myself. The specimen consists of thin veinlike millerite interspersed between calcite, in massive calcite. It is a certainty that were you to etch this out, there would be much more inside, probably better preserved within the calcite. Most of the millerite showing is to my eye noncrystalline or microcrystalline, and as vein filling. But its there, and the piece was verified by Herb Obodda, who pronounced it legit.