Tufa

Uncommon card · No. 199917

Tufa (tuft, calc-tuff or tophus) is a variety of limestone formed when carbonate minerals precipitate out of water in unheated rivers or lakes. Geothermally heated hot springs sometimes produce similar (but less porous) carbonate deposits, which are known as travertine or thermogene travertine. Tufa is sometimes referred to as meteogene travertine.