This is a very elegant cluster of cuprites, that have been partially replaced by malachite. This is a classic, ancient locale. Few old specimens are available. My understanding is that specimens like this are still found in small pockets, from time to time - but usually singles and small crystals, not a big piece like this. You can tell by the weight that the replacement is only partial, and cuprite remains at the core of the specimen. But on the surface, it is solid malachite. A rare, interesting locality piece!