Hormuz is an island at the mouth of the Persian Gulf, off southern Iran, and it is not made of rock. It is a dome of salt, pushed up from below through the sea floor. Salt is restless: lighter than the rock around it, it keeps creeping slowly upward and outward, carrying its minerals with it. Some seventy of them colour the island. In the dry washes of Rainbow Valley the slopes lie stacked band over band in red, ochre, yellow and violet. The crust crunches underfoot in places; in others it is soft enough to smear between your fingers like dry pigment. At Red Beach the sand is a deep iron-red that leaves dark crimson tracks behind you and tints the surf as it breaks. Round the shore the ground keeps changing cove by cove, red to ochre to silver-black sand, with small fishing hamlets between the headlands.
A salt stream leads up to the caves of the Salt Goddess, where crystallised salt coats the walls in ripples and folds; run a finger along the rock and you taste the sea locked inside it, while the crust crackles underfoot. On the northern point stands the Portuguese fort of red stone, its bastions, cisterns and ruined chapel still standing over the water. From the ramparts you are looking out over the Strait of Hormuz, the tanker channel that made this bare rock worth fighting over. An old saying held that if the world were a ring, Hormuz would be its jewel, and its port was once among the richest trading places on Earth. The coloured earth has since become an art material: villagers and visiting artists rake the powdered soils into enormous ground carpets on the shore, one of them spread across some 1,300 square metres in about ninety colours. Only the cool months, roughly November to March, are walkable at all; the Gulf summer out here is among the worst heat on Earth. And the red earth is clean enough to eat — the islanders grind it into a spice and put it on bread and fish.