This piece was originally part of the collection of Phelps-Dodge, who owned the mine when it was mined in the late 19th Century.  The upper two-thirds of the piece comprises a rich covering of royal blue azurite "rosettes" of bladed azurite crystals up to 5mm in size. These grew on a matrix of silky-textured botryoids of primary malachite which was then overgrown by iron oxide, visible both as a limonite matrix and as a black botryoidal crust intergrown over the bottom third of the piece with mm-scale octahedral cuprite crystals with a green coating of secondary malachite. The back of the piece is dominated by this assemblage.