Marble or travertine — which should you specify?

What is the actual difference between marble and travertine?

Marble and travertine are both calcium carbonate stones, but they form differently, and the difference shows up as porosity. Marble is limestone that has been recrystallised under heat and pressure, which closes up its pore structure. Travertine forms from mineral springs depositing calcite, and the gases escaping during that process leave the cavities travertine is known for.

That single structural difference drives almost every practical decision that follows: how much water the stone takes up, how it behaves in frost, how it is finished, and how it is filled.

How do the technical numbers compare?

The figures below are measured under the European test methods, which is what a specification will reference. Density is EN 1936, water absorption at atmospheric pressure is EN 13755, and uniaxial compressive strength is EN 1926.

Denizli travertine has a bulk density of roughly 2,410 to 2,720 kg/m3, absorbs about 2.6% of its weight in water, and reaches 50 to 87 MPa in compression. Muğla White marble, quarried a few hours away, has an apparent density around 2,760 kg/m3, absorbs about 0.15%, and tests at approximately 66 MPa.

Note what that comparison does and does not say. Travertine absorbs roughly seventeen times more water than that marble, which is the number that matters for wet areas and frost. But travertine is not the weaker stone in compression — its range tops out higher than the marble figure. Strength and porosity are separate properties, and conflating them is the most common mistake in stone selection.

Which one belongs outdoors?

Both can go outdoors, and the honest answer depends on frost rather than on the marble-versus-travertine question. Water inside a pore expands about 9% when it freezes, so absorption is the property that predicts spalling in a cold climate.

For an exterior application in a freezing climate, ask the supplier for the frost resistance result under EN 12371, not just the absorption figure. Absorption is a useful proxy, but frost resistance is the property actually being specified, and it is tested directly.

In a climate that does not freeze, travertine is a well-proven external paving stone — the reason it is the default around pools is that its surface stays comparatively cool and its texture gives grip underfoot.

Which one is easier to live with indoors?

Marble takes and holds a polish that travertine cannot, which is why marble dominates where a reflective surface is wanted. Travertine is more forgiving of wear, because its surface is already varied and small marks read as part of the stone.

Both stones share one vulnerability, and it is worth stating plainly:

• Acids etch both. Vinegar, lemon juice and most limescale removers damage the surface.
• Etching is physical damage, not a stain. It cannot be cleaned off, only re-honed or re-polished.
• A penetrating sealer reduces staining. It does not prevent etching.

What about filled versus unfilled travertine?

Travertine is sold filled, where the natural cavities are grouted flush, or unfilled, where they are left open. Filled travertine behaves more like a conventional tile and is the usual choice for interior floors. Unfilled travertine keeps more texture and grip, which suits external paving, but the open cavities collect dirt and are harder to clean.

Marble has no equivalent decision, because a recrystallised stone has no cavities to fill.

So which should be specified?

Specify marble where a polished, low-absorption surface is the point: bathrooms, feature walls, interior floors in a temperate climate. Specify travertine where texture, grip and a warmer colour range matter more than reflectivity, and outdoors in climates without hard frost.

Where the decision is genuinely close, let the test data decide rather than the category name. Two travertines from different quarries can differ more from each other than a travertine differs from a marble — which is why General Stone World publishes the values per stone rather than per material type.