tufa

[Ital. tufo =a porous stone.] Petrol.: A name given to a light, porous, calcareous stone, sometimes having the aspect of a sandstone, at others earthy and inclosing the decomposed remains of vegetable substances. Composition: A carbonate of lime; deposited by springs, rivers, and heated waters which have traversed calcareous rocks. Sometimes, though incorrectly, spelled tuff. tu-fa-ceo us (ca h), a. [TUFA.] Pertaining to tufa; consisting of or resembling tufa or tuff. tufaceous-limestone, s. Petrol.: A limestone (q. v.), which partakes of the characters of a tufa (q. v.).