Hierve el Agua mountainside. The water has a temperature of . As the water runs down the rock face, it forms large stalactites similar to those found in caves. The flow of water from the spring varies significantly between the dry and rainy seasons. 95% of the surface rock formations are of calcium carbonate; however, lower layers of both rock and water currents are little known as they are sealed by the above layers. The calcium carbonate gives the formations a white or near white appearance, but other minerals that can be present in the water, such as silver, barium and iron can
Sittanavasal Cave ASI) were applied over dry plaster surfaces without any adhesive grove; the process involved a chemical reaction of lime water which absorbed oxygenin the air and getting converted by a carbonisation process into insoluble calcium carbonate, which enabled the pigments to adhere to the surface. At the initiative of Pudukkottai State, during 1937–39, the paintings were cleaned, and then given a preservative coating. Also, the damaged portions of the plastering were injected with cementing material and the paintings were also retouched. The condition of paintings are deteriorating. Sittanavasal Cave Sittanavasal Cave (also, Arivar Koil) is a 2nd-century Jain complex of