Excellent and historic, this very fine Pyromorphite probably dates to the early or mid-1800's. The crystals are lustrous, grass-green, and hexagonal. Averaging 2-3 mm, some of these sharp Pyros exhibit mild hoppered growth. The matrix is a fine, granular sandstone with a limonitic color. The crystals are not large, but the provenance of having been in the Carl Bosch and Smithsonian collections previously adds greatly to what was already an excellent specimen. Most mining at these ancient lead mines ended in the 1880's. A very fine and aesthetic small cabinet size piece, this has been preserved intact for at least 120 years, and possibly double that. The label in Carl Bosch's hand indicates a purchase date on the back of Dec 9, 1907 and source initials given as "M.Y." These original Bosch labels are precious, few, and seldom seen for sale. The provenance is very important as you can see here: http://minrec.org/labels.asp?colid=205. He was awarded the Nobel Prize in Chemistry in 1931 for his work on high-pressure ammonia (fertilizer) synthesis.