Simple Lithology

travertine

http://resource.geosciml.org/classifier/cgi/lithology/travertine

broader chemical sedimentary material
narrower travertine
limestone
narrower travertine
definition Biotically or abiotically precipitated calcium carbonate, from spring-fed, heated, or ambient-temperature water. May be white and spongy, various shades of orange, tan or gray, and ranges to dense, banded or laminated rock. Macrophytes, bryophytes, algae, cyanobacteria and other organisms often colonize the surface of travertine and may be preserved, to produce the porous varieties. more like this
example
calcareous sinter more like this
onyx marble more like this
tufa more like this
source Neuendorf et al. 2005; http://en.wikipedia.org/wiki/Travertine; Chafetz, H.S., and Folk, R.L., 1984, Travertine: Depositional morphology an dthe bacterially constructed constituents: J. Sed. Petrology, v. 126, p.57-74. more like this
type
Resource
Concept
in scheme simplelithology
is primary topic of travertine