Rawhiti Cave become increasingly finer deeper down into the cave. A short walking track leads halfway down into the cavernous opening to a viewing platform. The diverse twilight-zone flora near the entrance of Rawhiti Cave makes this cave nationally significant. Over long periods of time, plant growth on the cave formations causes them to grow towards the sunlight as more calcium carbonate is deposited regularly on top of the plant growth. This phenomenon, called phytokarst, is most evident on the larger stalactites near the cave entrance, which are strongly curved outwards due to the heavy moss and fern growth on their sunlit
Calcium carbonate ingredient in many household cleaning powders like Comet (cleanser) and is used as a scrubbing agent. In 1989, a researcher, Ken Simmons, introduced CaCO into the Whetstone Brook in Massachusetts. His hope was that the calcium carbonate would counter the acid in the stream from acid rain and save the trout that had ceased to spawn. Although his experiment was a success, it did increase the amount of aluminium ions in the area of the brook that was not treated with the limestone. This shows that CaCO can be added to neutralize the effects of acid rain in river ecosystems.