Is travertine a form of limestone?

Question

Some books say that it is a form of limestone, others say it is not limestone. What is travertine exactly in terms of it's principal mineral/s?

Answer 1

Travertine is calcium carbonate in the form of aragonite and (or) calcite. As you've noticed, some folks group it with limestone and some don't. I suppose that those folks who don't like it grouped with limestone prefer to make a distinction based on depositional histories rather than chemistry--with travertine forming from spring deposits or in wet caves and marine limestone beds forming from marine deposits. It is more informative to make the distinction. Some commercial stores that sell counter tops and so forth group it with the marbles (metamorphosed limestone) because most buyers don't really know or care about the differences in depositional or metamorphic histories.

Answer 2

marble