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On a sunny morning, Greivin makes his way down to the Madre de Dios River with a sack slung over his shoulder. He is not alone: Jurgen, Memo, and I follow behind, trying to keep up as he moves forward with the enviable ease of a campesino, first through the undergrowth and then across the stones of the riverbed.
We are there because we want to learn how to recognize agates. But what truly fascinates me is something else: the way Greivin is able to discern what is valuable among so many rocks that, to anyone else, would look the same.
From a distance, he senses a texture. He crouches down, picks up a stone, studies it, turns it over, and lets it fall, again and again, until his hands—trained by experience rather than classrooms—detect something different: a dull sheen along one side, a pattern that barely hints at itself. “This one has a heart,” he says, before slipping it into his sack.
He never studied geology or art, yet he has learned to look with a kind of patience that is not taught at university. Agates are remarkably hard: they are made of almost pure silica, in the form of chalcedony. We find them as rounded blocks in the river because the rock that once held them disintegrated, while they—more resistant—travelled on with the current.
By midday, the rain arrives. Our plan to go to the Pacuare River, another place where Greivin has found agates, is left for another time. Greivin shoulders the sack uphill, carrying half a dozen heavy stones as if it were nothing. He does this every week—not for money, he says, but because “it takes me somewhere special, it pulls me out of routine.”
The Weave of the Invisible
When Greivin cuts one of his stones, the mystery opens in layers. Lines appear that resemble frozen rivers, petrified whirlpools, circles that tell a story without words.
Agates are born inside volcanic rocks, within cavities formed when lava cooled and left empty spaces behind. Much later—over thousands or even millions of years—silica-rich fluids flowed through those spaces, depositing extremely fine layers that gradually hardened. Layer upon layer, the stone slowly wove its memory.
This is how their bands are formed, like the memories of a life. And those memories may be ochre, green, translucent, milky… Everything depends on the conditions under which they formed: traces of iron or manganese, more or less acidic water, the presence of oxygen. Each layer is a record of that history, and every agate is unique, like a fingerprint.
I think of Agatha Christie, the writer who turned mystery into art. Christie did not merely invent enigmas; she unfolded them with the precision of a stone cut at exactly the right point. In her novels, as in agates, the truth waits patiently until someone decides to really look. To cut in order to see. Perhaps that is why my daughter is named Isabelle Agatha: because I wanted her to carry a name that held both the secret and its revelation.
Unique and Irrepetable Traces
Entering Greivin’s house is to discover a world with its own order: rocks everywhere, filling the yard, the corridors, and the corners where chickens and ducks wander freely. Greivin points to each group with precision; he knows what he found, where he placed it, and what it might reveal once cut. “If you want, I can split a few,” he says enthusiastically.
Curiosity guides each stone toward the saw at the back of the yard. There, Greivin and his teenage son spend hours cutting and washing, looking and marvelling. When they are finished, the polished pieces rest on a wooden table in front of the house. Some he gives away, others he sells. I, as usual, buy more than I should carry.
I think that agates wear their irregularities and folds with pride. They know this is what makes them unique. We, far too often, wish for the opposite: we try to erase our cracks to appear younger, more whole, without understanding that they are the very proof of having lived.
I stop in front of the agates, dazzled by so much beauty. In them, spontaneity becomes harmony. Fluidity turns into a new, petrified life. Agates do not aspire to perfection; they accept their history and give it form. In their bands, one can glimpse what we often prefer to hide: the trace of time, the pauses, the wounds. And then a suspicion arises—that beauty is not born despite the marks and grooves, but because of them.