Chapada Diamantina National Park

Listen first. Water runs over stone somewhere close by, steady and unhurried. The air smells of wet rock and warm leaves. Under your feet the ground is pale sandstone, grained and rough, worn smooth in places by countless boots and centuries of rain. Ahead, the land rises in flat-topped walls of rock, their sides striped grey, orange and rust. Welcome to Chapada Diamantina, seen from its eastern edge, near the old mining town of Andaraí.

The name tells you two things at once. In Brazilian Portuguese, a chapada is a high tableland, a plateau with steep sides and a flat summit. Diamantina means diamond-bearing. This is a high plateau in the heart of the state of Bahia, in northeastern Brazil, and for a long time people came here for one reason only. They came for the stones hidden in its rivers and gravel beds.

The diamond rush began in the nineteenth century. Word spread that diamonds lay in the streams of the plateau, and miners arrived from across Brazil. Local people call these miners garimpeiros, which means independent prospectors who worked by hand. They dug, sifted and washed gravel in the riverbeds. Towns grew quickly around the richest deposits. Andaraí was one of them, and so was Lençóis to the north.

Here is a detail many visitors miss. The plateau did not only produce clear gemstones. It also produced a dark, rough kind of diamond, often called carbonado, or black diamond. These stones were not prized for jewellery. They were valued for their hardness, and they were used in industrial cutting and drilling tools. So some of the stone from these hills may have ended up working in machines far from Brazil, not on anyone's finger.

The boom did not last. As the easy deposits ran out, the miners moved on, and many settlements shrank. Some were almost abandoned. The clearest example lies just above Andaraí, in the village of Igatu. There, entire streets of dry-stone houses stand without roofs. The walls were built from flat slabs of local rock, stacked without mortar. Today a small community still lives among the ruins, and the quiet there feels very different from the noise of the boom years.

In 1985, a large part of the plateau became a national park. The aim was to protect the rivers, caves and mountains that mining had once torn apart. Mining was gradually pushed out of the protected area, and many families turned to a new kind of work. Former garimpeiros and their children became trail guides. They knew every path, every pool and every cave, because their parents had worked them for diamonds.

Now look at the water. Many rivers here run the colour of strong tea, or even dark cola. This is not pollution. The colour comes from tannins, natural compounds that leach from plant matter as water filters through the soil. In shallow pools the water looks golden. In deep pools it turns almost black. When it falls over a ledge, the foam can look like cream poured into coffee.

Andaraí sits close to some of the park's best-known water features. To the north lies the Marimbus, a broad wetland where rivers spread out into reed beds and slow channels. Visitors often cross parts of it by canoe, sliding between tall grasses. It is a very different landscape from the dry rock above. Herons stand still in the shallows, and the only sound may be the paddle entering the water.

The area around Andaraí is also known for its caves and flooded caverns. The most famous is the Poço Encantado, the Enchanted Well, reached by road from town. Inside, a pool of clear blue water fills the floor of a deep cave. During part of the year, sunlight enters through an opening and falls as a single beam into the water. The pool is so clear that rocks far below the surface seem close enough to touch. Nearby, the Poço Azul, the Blue Well, offers a similar light, and in some seasons visitors can float on its surface.

Lift your eyes to the plants around you. The high ground carries a type of vegetation that ecologists call campo rupestre, which means rocky grassland. It grows on thin soil over stone, and it is full of species found nowhere else. Look for orchids clinging to rock, bromeliads with stiff rosettes of leaves, and small shrubs with leathery foliage. Lower down, the dry scrubland of the Brazilian interior mixes with patches of greener forest along the rivers.

The plateau also has a spiritual life of its own. Locals speak of Jarê, a religious tradition found mainly in this region. It blends African-Brazilian practice with Catholic and Indigenous elements. You will not see it on a trail, but it remains part of the culture of the small towns. Listen at a local festival, and you may hear drums that carry this mixed heritage forward.

For a visitor today, the best way to understand this place is on foot. Distances are long, trails are rough, and paths are not always marked. Most people hire a local guide, and in many areas this is strongly encouraged. A good guide will tell you about the rock and the birds. Often they will also tell you about a grandfather who once washed gravel in the same river where you are now standing.

So pause for a moment before you move on. Notice the colour of the water near you, and the stripes in the cliff above. Somewhere in that rock, perhaps, a few diamonds still wait. The miners have mostly gone, and the river keeps running over the same stones. As you walk back toward Andaraí, listen once more for the water. It was here long before the diamond rush, and it is still here now.