Third Worldwide Occurrence of Juangodoyite, Na2Cu(CO3)2, and Other Secondary Na, Cu, Mg, and Ca Minerals in the Fore-Sudetic Monocline (Lower Silesia, SW Poland)

Na-Cu carbonates are relatively rare secondary minerals in weathering zones of oredeposits. Hereby we describe mineral composition and crystal chemistry of the most importantsecondary (Na)Cu minerals and their Na- and Mg-bearing associates forming rich paragenesis inRudna IX mine. A non-bulky Ca-rich dripstone-like paragenesis from Lubin Główny mine is alsocharacterized, using Powder X-Ray Diffraction, Rietveld, and Electron Microprobe methods. Lightblue juangodoyite (3rd occurrence worldwide) and darker chalconatronite are the most importantmembers of the Rudna IX paragenesis, being associated with malachite, aragonite (intergrown withhydromagnesite and northupite), and probably cornwallite. Most of the minerals are chemicallyclose to their ideal composition, with minor Mg substitution in malachite. Cu chlorides are mainlyrepresented by clinoatacamite and probably herbertsmithite. Additional, minor phases includetrace Cu minerals langite, wroewolfeite, and a lavendulan-group mineral, and monohydrocalcite.Separate halite-rich encrustations are shown to be filled with eriochalcite, ktenasite, and kröhnkite.The most likely to be confirmed coexisting species include paratacamite, wooldridgeite/nesquehonite,johillerite, melanothallite, and kipushite. The Lubin paragenesis mainly comprises aragonite, gypsum,rapidcreekite, and monohydrocalcite, with trace vaterite. Blue colouration is mainly provided by ayet unspecified Ni-, Co-, Mg-, and Mn-bearing Cu-Zn-Ca arsenate mineral close to parnauite.