Kalktuff

Kalktuff is a geological term referring to a porous, calcareous rock formed from accumulated tufa. Tufa itself is a type of limestone deposited by mineral springs, especially hot springs. As water rich in dissolved calcium carbonate flows over the surface, the carbonate precipitates out, often forming layered structures. Over time, the accumulation and lithification of these tufa deposits can create a rock mass known as kalktuff.

The porous nature of kalktuff is a distinguishing characteristic. This porosity arises from the way the tufa forms, often creating hollows and interconnected spaces as mineral deposits build up. This texture makes kalktuff relatively lightweight compared to denser rocks. It is typically found in areas with active or recent geothermal activity and where groundwater has a high mineral content.

Kalktuff can exhibit a range of colors, often appearing white, cream, or light brown, depending on the presence of impurities and the specific mineral composition. It is sometimes used as a building material, particularly in regions where it is locally abundant, due to its ease of working and its distinctive appearance. However, its porous nature can also make it susceptible to erosion and weathering. Examples of kalktuff formations can be observed in various geothermal regions around the world.