from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Calcareous tufa, a porous or spongy deposit of calcium carbonate found in calcareous mineral springs.
from the GNU version of the Collaborative International Dictionary of English
- n. See under calcite.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a soft porous rock consisting of calcium carbonate deposited from springs rich in lime
ALABASTER) and other stalagmitic deposits also consist of calcite, and so do the allied deposits of travertine, calc-sinter or calc-tufa.