Another fine specimen at the Holden / Marolt Mining and Ranching Museum in Aspen, Colorado — this time, it’s a sample of wulfenite:
Wulfenite has the chemical formula PbMoO4, and so is a secondary ore of both molybdenum and lead. It’s typically found in mineral zones formed by hydrothermal deposits, and prized by mineral collectors. It can be found in a number of colors, but shades of orange, red, and yellow seem to be dominant. It was first described in 1845, and is named after the Austrian minerologist Franz Xavier von Wulfen (1728-1805), who authored a monograph on the lead ores of Bleiberg, Austria.