Tufa Tufa The Gripping Hand Category="Sedimentary rocks"[image] Tufa is the name for an unusual geological formation.

Tufa is a rough, thick, rock-like Calcium carbonate deposit that forms by precipitation from bodies of water with a high dissolved Calcium content. Tufa deposition occurs in seven known ways:

  1. Mechanical precipitation by wave action against the shore. This form of tufa can be useful for identifying the shoreline of extinct lakes (for example in the Lake Lahontan region).
  2. Precipitation from supersaturated hot spring water entering cooler lake water.
  3. Precipitation in lake bottom sediments which are fed by hot springs from below.
  4. Precipitation from calcium-bearing spring water in an alkaline lake rich in carbonates.
  5. Precipitation throughout the lake as the lake dries out.
  6. Through the agency of Algae.
  7. Precipitation from cold water springs (for example in the foothills of the Rocky Mountains near Hinton, Alberta)

There are some prominent towers of Tufa at Mono Lake and Trona Pinnacles in California, USA, formed by method 4, above. Tufa is also common in Armenia.

Usage note: The rock type "tufa" is commonly confused in name by laypersons with the rock type "Tuff", which is a rock formed from welded volcanic ash. These rocks are nothing like each other.

Tufa is occasionally shaped into a planter. Its porous consistency makes tufa ideal for alpine gardens. A concrete mixture called Hypertufa is used for similar purposes.