What the absence of cavities changes
A travertine coping is chosen partly for the texture its open voids give a wet hand. A limestone has no such voids, so its surface has to be worked to get there.
That is why brushed and natural faces lead this small range rather than honed ones. A brushed limestone is run under abrasive brushes until the softer material wears back and the harder grains stand slightly proud, which produces a texture the stone did not arrive with.
Shell stone is the exception
One of the stones here is shell stone, a limestone made almost entirely of shell and coral fragments.
It is the one limestone with texture of its own, because the fragments and the spaces between them are the surface. That has made it the traditional coping around the Gulf and the Caribbean, where it is quarried, and it is the closest a limestone gets to behaving like a travertine. Limestone pavers covers the decks that go with it.
Thicker than paving
These run at an inch and a quarter and an inch and a half, which is more than most of the paving on the same terrace.
A coping cantilevers over the pool edge with nothing under the overhang, and it is gripped and leaned on constantly. Depth is what stops the front edge breaking away where somebody pulls themselves out of the water. Pool copings sets out the profile in full.
Warm, and that is the point
The colors here are beige and brown, which is limestone behaving normally: the warm tones come from iron in the original sediment.
A pale warm stone around a pool is not a style decision so much as a heat one. It returns more of the sun than it absorbs, which is what keeps a coping usable by bare hands and feet at the hottest part of the day, and it is why the traditional pool stones are creams rather than grays.
Limestone against travertine at a pool edge
A travertine is more porous and more textural and it has been the default for decades. A limestone is denser, finer grained and holds a sawn or worked edge more crisply.
Neither is the better stone in the abstract. The travertine gives more texture with less work and the limestone gives a cleaner edge and a quieter face. What either requires is stated by its maker on the product page. Travertine pavers is the other tradition.
12x24 and 16x24
The two sizes here are 12x24 and 16x24, and both are lengths rather than areas: a coping is counted along the perimeter of the pool.
The 16 inch depth is the one to look at where the coping has to overhang the shell and still leave a comfortable width to sit on. A 12 inch piece gives a narrower edge and more pieces around the same perimeter, which means more joints in the most visible line of the whole surround.
Where it goes
The edge of a pool or a spa, the top of a raised wall, a step nosing on a terrace and any exposed edge where a sawn stone face would be too sharp.
Limestone tile covers the material indoors and pool and spa paving the whole surround.
