Here today, gone tomorrow

He works not in a linear way, but in what he calls "spirals" or "cycles". His most recent paintings, for example, refer to certain geometric interventions that he made on newspaper photographs eight years ago. Themes or techniques lie dormant in his work for years, then return in an extensive series.

Some of the objects reflect Orozco's preference to work at a table, wherever he can find space. "My wife tells me I'm always making my work on the kitchen table," he says, adding: "I'm not a very good cook."

The kitchen is an appropriate starting point. As we walk through his installation, Orozco picks up one of his terracotta sculptures, Four and Two Fingers, and mimes the gesture that went into making it - "almost how you make bread".

The form has an elongated smooth, organic shape, with two dimples at each end and two holes in the middle. "It's about the body pressing against material," he says. As he lifts up the piece, he inserts his thumbs into the two holes. The wooden ball he calls " technology" - of the simplest kind.

Work is quick, fragmentary, simple. He might make a series of drawings with ink on the palm of his hand, or clay sculptures that in a few seconds are twisted into a vaguely organic shape, ready for firing.

One image has him in a street market of empty stalls in Brazil, with a pile of unsold oranges. Passing through the market he placed a single orange on each stall, snapped the result and moved on. I'm guessing he never looked back.

His photographs mark these " sculptural events" - strange, modest configurations, which recycle materials and suspend our sense of their original function. Recycling is implied, adding a political quality to the work.

Orozco is interested in the world's discards. "Lintels" consists of sheets of lint removed from laundromat dryers and suspended across the gallery on wires like washing lines.

All humanity is here, compacted into its own dust. I first saw the work not long after 9/11 in New York. It resonated mutely then and is still a haunting site in Diana's Hyde Park. "It was the mood," Orozco says, "living with the smell and the dust."

The piece forms part of what Orozco lightheartedly describes to me as the "dirt room", where he also displays etchings derived from the lint sheets. The prints generate a new perspective. We examine them closely, Orozco pointing out details in the paper that he confesses he wouldn't care to examine too closely in the original detritus.

The exhibition reveals a strong sense of geometrical order. There are patterns to everything, and one object generates another. A drawing might be a single flourish of the hand, or an acutely complex system developed over six months on a blackboard.

A new series of paintings continues a 10-year process of interrupting the surface with constructivist-style bisected circles and ellipses. He talks me through the strict rules he follows in each one, indicating what he calls the "centrifugal point" of a painting.

Only when he finds such internal logic in the world around him does he take a photograph. "Art is one part finding and making; the other part is what the spectator makes of a thing," he suggests.

One of the few photographic images on display is of a rough-hewn construction, held together, seemingly, by wooden poles and caked, dried earth. Dapples of light pierce through its woven roof.

There is a strong sense of innocent encounter with a place quite untouched. Orozco reveals to me that it is a mosque in Timbuktu. "There is geometry, there is dust," he says. "There is simplicity. I cannot imagine a more mystical space."

I would call him a romantic conceptualist. The term might seem contradictory - conceptual art is often thought to be all in the mind, needing neither artist nor spectator. Orozco's conceptualism, though, is about being there, or rather passing through, just for the moment. The work is engaged with the ephemeral, and the artist is always moving on.

Gabriel Orozco at the Serpentine Gallery, 1 July-30 August.