Travertine
slabs and tile

Travertine is a freshwater limestone that forms at mineral springs. Water saturated with dissolved calcium carbonate reaches the surface, pressure drops, carbon dioxide escapes, and the mineral drops out of solution and builds up in layers. Gas escaping through those layers is what leaves the cavities travertine is known for, and the layering is what gives it direction. The stone is a record of moving water, which is why it never looks manufactured.

That layering is the reason the cut matters so much. A block sliced across the bedding planes, called cross cut, produces the cloudy, roughly circular figuring most people picture when they hear travertine. Sliced along the bedding planes, called vein cut, the same block produces long parallel striations that read as linear and architectural. These are the same stone and they belong in different rooms. Vein cut stretches a wall horizontally. Cross cut settles a large floor down.

Filling is the second decision and it is genuinely reversible only in one direction. The cavities can be filled with matching resin or cement to give a continuous surface, which is what you want under a countertop, in a shower, or anywhere that has to be wiped down. Left unfilled, the surface keeps its pores and its shadow, and on a feature wall that texture is the entire point. Unfilled travertine on a kitchen counter will collect crumbs, and no amount of sealing changes that.

For Miami specifically, travertine has one property worth more than its looks. It stays comparatively cool underfoot in direct sun and, in a textured finish such as Sandblasted or Bushammered, it holds grip when wet. That combination is why it has been the default around pools here for decades. It is a limestone, so it etches like marble, and around a chlorinated pool or a salt deck the honest recommendation is a textured finish and a sealer, checked yearly.