Again, the study of stalactites and stalagmites is well established for over a century. Even 85 years ago, there were published peer research papers that made a comparison between the formation of stalactites and stalagmites in the caves and on man-made structures like bridges. It is not the same material, it involves different processes and mechanism. Stalactites and stalagmites preserve information about the climate, various stages of glaciation, do have also isotopes for the radiometric dating. Also, stalactites and stalagmites do contain other elements like iron, copper, manganese, and nickel.
Other information that can be revealed from the caves points to a plate tectonics like a closure of the seaways, which affected the precipitation and stalactites/stalagmites creations. Stalactites and stalagmites in the caves can reveal the Australian plate push northward, closing the Indonesian seaway and redistributing ocean current circulation; Messinian Salinity Crisis, and so on. All these finding are in line with information that can be observed from other fields that prove the Earth age be well beyond beliefs held by fundamentalists. Even top Catholic universities do not dispute it.