Deep chocolate and russet. Rich indoors and on shaded patios — hot in full sun.
Walnut travertine (noce, in the Italian trade name) is the dark end of the travertine range: chocolate browns shot through with russet and the occasional cream streak. Against white stucco or a light coping it is one of the sharpest contrasts available in natural stone.
Its limitation is heat. A dark stone in Florida or Arizona sun will reach temperatures that make barefoot use unpleasant, so walnut belongs on covered patios, shaded walkways, interior floors, and vertical cladding rather than on an open pool deck.
Used vertically it is exceptional — the tumbled edge and the depth of colour give a wall real weight, and heat is irrelevant on a surface nobody stands on.
Each of these opens the library filtered to everything suitable for that use, so you can see what Walnut Travertine is competing against.
Post the project and contractors working in your county bid on it — with this stone already specified.