A very, very fine and rare specimen of large crystals of Cervandonite, which is a rare earth arsenate containing all kinds of interesting ingredients such as Ce, Nd, La, Titanium and Aluminum, and some Arsenic for good measure. It is like a witches' brew of rare earths with oxygens added. These crystals are gorgeous and extremely large for the species. The cluster is 1.5 cm across, and complete all around. They are undamaged, and show classic curvature for this material. From the collection of Matteo Chinellato of Italy.Joe Budd Photos