Linnaeite is an uncommon cobalt sulfide. The matrix on this old-time thumbnail is richly covered with sparkly linnaeite microcrystals and massive, layered linnaeite. The linnaeite has an interesting purple iridescence. This rich and highly representative piece is from the historic La Motte MIne of Madison County, Missouri in the old Missouri Lead Belt of southeastern Missouri. This is the oldest lead mine west of the Mississippi River, opening in 1720. Classic material accompanied by an expertly handwritten, faded label from an older collection. The collection this came out of was a museum stash dating to prior to World War I.