These "balls" started coming out in January, from one reliable source of mine who works directly with miners at Tonglushan (literally "Green Copper Mountain" in Mandarin), which by the way is also the world's oldest continuous working copper mine. It has been active since the Chinese Bronze Age 3500 years ago, and there is a historic museum atop the old ruins. Nowadays, they mine deep underground with huge trucks and modern mining. Tonglushan is the recently productive source of many modern copper minerals from China including Malachite in stalactites and sheet forms, the strange chalcocite "balls" in matrix that came out a few years ago, sparkly Pyrite on Calcite, Calcites of different colors, Gypsum, and many other species. The modern entry is just down the road from the museum and the archaeological grounds of the old smelters and kilns of ancient times.