Chrysocolla replaced by Malachite (?) (ex Willard Wulff Collection)

Item Description

This specimen comes from the collection of Willard W. Wulff (1904-1998) of Colorado Springs, Colorado, a prominent figure and collector of Colorado minerals. Wulff was one of the founding members of the Colorado Springs Mineralogical Society in 1936. You can read Willard's bio on the Mineralogical Record website here ( http://www.minrec.org/labels.asp?colid=1528 ). The piece comes with a typed label from Wulff on one of his famous 3x5 index cards stating that it was purchased from Pardo's Rocks and Minerals in Tucson, Arizona. The label also says the piece is "Chrysocolla replacing Malachite ??", but I think it should be the other way around as I can clearly see blue Chrysocolla UNDERNEATH the green mineral on the exterior, so it should be Chrysocolla REPLACED BY Malachite (??). There are dozens of pristine botyroidal aggregates measuring up to 6 mm coating the matrix on this specimen. I don't have much a reference for Chrysocolla from Chihuahua, but I don't know where else it could be from, so I'm leaving it as written on the label.