This is a very old specimen characteristic of what you can find documented in books or museums from the early mimetites found at Tsumeb, back before WWI (1890s-1910 or so). It turned up in an old collection in Europe recently. The crystals are robust elongated prisms, to 2.2 cm in length. While there is some damage, the piece is largely unscathed and is remarkable for its size and 3-dimensional presentation, given its age. It is 720 grams. Joe Budd Photos