Cioclovina Cave in Romania’s Southern Carpathians is a world-renowned cave site for its paleontological, anthropological,and mineralogical (type locality of ardealite) finds. To date, over 25 mineral species have been documented, some unusualfor a cave environment. This paper presents details on the occurrence of collinsite [Ca2(Mg,Fe2+)(PO4)2x2H2O], atacamite[Cu22+Cl(OH)3], and kröhnkite [Na2Cu2+(SO4)2x2H2O] based on single-crystal X-ray diffraction, electron microprobe, stable isotopeanalyses, and scanning electron microscope imaging. This is the first reported occurrence of kröhnkite in a cave environment.Atacamite represents the weathering product (in the presence of Lower-Cretaceous limestone-derived chlorine) ofcopper minerals washed into the cave from nearby ore bodies. Atacamite and kröhnkite have similar sources for copper andchlorine, whereas sodium probably originates from weathered Precambrian and Permian detrital rocks. Collinsite is believedto have precipitated from bat guano in a damp, near-neutral pH environment. The results show the following sequence ofprecipitation: ardealite-brushite-(gypsum)-atacamite-kröhnkite. This suggests that the observed mineral paragenesis is controlledby the neutralization potential of the host-rock mineralogy and the concentrations of Ca, Cl, Cu, and Na.