tra-ver- means across.
tra- means across.
Across the grain is a type of cut.
So, travertine means cut across the grain.
It could cut slanted across, or straight across, or whatever.
Nothing is meant precisely.
Take nothing literally.
Read nothing into it.
Long ago, languages had fewer terms. Vocabulary was basic.

If anyone feels they want to object because grain means wood, they may consider it means cut across the layers, or across the striations. Striation is another term. Layer is better than striation in my opinion.

When a stone has soft and hard parts all mixed together, cutting across layers makes a lot of sense. Then, the soft parts become holes, or may become holes.

This is my take on it.

Hth.

It is a calciferious form of limestone produced typically at the mouths of hot springs. The holes are naturally occuring and can be left open or filled with a resin or grout. More on the subject below...

Here is a link that might be useful: Travertine Definition

Just to expand a little:
Geologically, what lazarususa said, plus: the mineral is made from calcium carbonate (same as limestone and marble). The crystal structure can be calcite or aragonite.

Etymologically, it is a corruption of Tibur, the region of Italy now known as Tivoli, where the material was obtained long ago:

Origin of TRAVERTINE
French travertin, from Italian travertino, trevertino, from Latin tiburtinus, adjective, of travertine, literally, of Tibur (Tivoli)
First Known Use: 1730

In the Italian version of the wikipedia article on Travertino, nobody has written that Tivol- was the root behind Traver-.

i believe some etymology can be fabrication. For linguists it is not worth the effort to investigate, nor to comment without investigating. I believe that the more one knows about word roots the more one might corroborate that Tra- and Vert- do not derive from "Tibur".

Back to Square One:
across the layers,
across the sides,
across the lines,
tras the verts.
Vers- Vert- are sides or lines.
Verses are lines.

Cutting across the stone's layers = a cut that compensates for the stone having some soft parts = = allows the soft parts to disintegrate (which creates holes) and at the same time to remain a solid stone, useable as a stone cladding or a building stone.

David, I love you, you know that. However, your response is silly. You are trusting your hunches over the OED? And linguists don't take the effort to investigate, uhh, linguistics? And your reason to assert this is that the Italian version of Wikipedia doesn't reference Tivoli/Tibur? Here is a snippet from that page (and, no, I did not go and add it to the page):

In Italia, i travertini migliori provengono dalle zone ai margini del vulcano laziale[senza fonte], in particolare da Guidonia e Tivoli (che ha dato il nome al cosiddetto "travertino romano", detto dai latini "lapis tiburtinus"),

I like your independent-minded thinking, but obduracy does not become you.

It is fairly delicate stone, easily damage by heat and acid, including orange juice and tomatoes, and it wears reatively quickly if used as a floor. It needs to be sealed, and resealed unless grouted and polished.

I am not referring to the grout between tiles, but a slurry painted on the travertine, allowed to dry, then polished off.

The grout is often just a cement-type mix, often including powered travertine for an exact color match, the grout fills up the pores in the rock making it less susceptible to staining. Increasingly, however, urethane and other plastic-type grouts are being used because they never need sealing and are very tough. They can even be infused into the stone under relatively high pressure.

ditto the post from xoldtimecarpenter

angie, latin "lapis tiburtinus" is not proof that the word later became travertino. It is the opposite. Anyone reading the Italian quote will see that it does not disprove my stance. And the reason I mentioned going to the original languages Italian and Latin in the first place was to shed doubt on anything one may read in English.

So, yes, Travertine means there will be holes.

Tufa has holes in it too.

davidro1, please don't take this personally, but much Wiki-aything is unreliable. Very. Frankly, the way people quote Wikipedia like it's some authority is insulting and just plain p!sses me off. Anyone can put whatever they like there, without verification or credit. It's a blog on steroids.

It's like saying, "I saw it on the Internet so it must be true."

Case in point:
My entire website is duplicated there, including my typos. On another note, also without credit, without copyright respect, and without a by your leave...

When I change, correct, or update my site for subjects, authors, photographers, vocabulary (Sanskrit) etc., no one bothers to correct it -- typos either.

So the accuracy of my plagiarized site is questionable, whereas were someone to actually be able to take a look at the original? They'd see something constantly verified and ever-updating. And... I see that Wikipedia site quoted on other industry-related sites. Grrrr....

Just my opinionated 2cents.

this is correct. The English wikipedia has it that tibur begat travertino.
Long ago, someone else made a mistake. Wiki-copies it.

Apparently, to my embarrassment, I can match your obduracy.

The etymology I quoted earlier was from Merriam-Webster, although I implied it was from the OED (as I didn't anticipate it would matter). Here is the actual OED entry:

Pronunciation: /ÃÂtraevÃÂtên/
Forms: Also trevertine.
Etymology: travertino , older tivertino "a kind of stone to build withall" (Florio) tëburtënus Tiburtine adj. Compare French travertin , in Cotgrave trevertin .

Here is a quote from 1555, where the form is not yet "Travertine":

1555 R. Eden tr. Peter Martyr of Angleria Decades of Newe Worlde f. 340, And [silver] is often tymes founde in an other stone lyke vnto Treuertino or in Treuertino it selfe.

The etymology listed above the quote cites Florio, which is an Italian-English dictionary. The 1611 version is available online. It does NOT contain an Italian entry for travertino, but only for tivertino, (written as tiuertino) which it defines (in English) as "a kind of building marble." It also cites Cotgrave, which is a French-English dictionary. The 1611 version (coincidentally) of that is also available online, and it defines the French word Trevertin as meaning "A kind of marble or marble-like stone."

IMHO, the change to "travertine" (sometime between 1555 and 1730) may have been influenced by the roots you cite. However, it would be a remarkable coincidence if there were a word in Italian tivertino (written in Florio as tiuertino), a word in French Trevertin, and a word in English "Treuertino" in the 17th century, and then later an entirely new word "travertine" meaning exactly the same thing sprang into the English language based entirely upon your etymology of the root "tra-". You are free to believe this, of course, but Occam's razor would dictate otherwise. The readers of this forum will decide for themselves.

Here is a link that might be useful: Florio entry for tivertino