Copper crystals are actually rare at Tsumeb despite it being a copper mine in the past! This is an old, very rare specimen from the "green hill" days of the first oxidation level. Most copper was smelted. This survived. It was then in the collection of William Vaux and the Philadelphia Academy of Sciences for nearly 100 years until that collection was sold (legally but perhaps inappropriately) some years ago. Emplaced nicely on gray smithsonite, are masses of rounded, sparkly , bright to dark, copper. It is a beautiful specimen with impeccable provenance.