When Bong Joon-ho made movie history by winning a clutch of Oscars for Parasite, he held the statuettes together afterwards, making them kiss. There is something charming about Bong taking these longed-for, career-defining objects and bashing their golden heads together. We love our treasures – since antiquity people have carved and hoarded statuettes, stones, rocks, trinkets. This is a genealogy that runs from Stonehenge to today’s most Cartier-obsessed rapper. Parasite is unashamedly about wealth, class, longing, scamming: what we want and what we’ll do to get it. Incidentally, Elon Musk loved the film. I wonder who he rooted for in its frenetic final scenes – the closest thing I’ve seen to class warfare on screen.

At the heart of Bong’s taut tragi-comedy is a rock, a “viewing stone” a “symbolic gift” that drives his heroes, the Kim family, to inventive and deadly extremes in pursuit of more: more money, more opportunities, a better life. Geology – rocks, gems, stones – as a heavy-handed metaphor for wealth or class difference is common on screen. Uncut Gems opens with a scene featuring bleeding, injured mineworkers; in Gentlemen Prefer Blondes, money-mad Lorelei risks her reputation by getting embroiled with diamond-mine owner “Piggy” Beekman.

Parasite is more subtle than that. Its shocks are violent, sometimes funny; its chaos comes in exquisite, controlled bursts. The Kim family languish, unemployed, in their basement flat, folding pizza boxes for money. One fateful night son Ki-woo’s elegant friend, Min-hyuk, descends into the basement and presents the family with a suseok, or viewing stone: a natural rock collected in Japan, China and Korea. Min-hyuk says the stone is believed to bring material wealth to families, even if he dismisses the idea as “stupid”. Soon Ki-woo has taken over Min-hyuk’s role as English tutor to the daughter of the hyper-affluent Park family – with the help of a faked college degree. The family toast their success, and diligently create fresh personas and fresh scams to infiltrate the Park family home by stealth.

A knock-off – whether it’s a bag, a necklace, an accent or, in this instance, a slew of faked qualifications and personae – can often do the job of the real thing. The viewing stone emboldens the family to scam their way to a better life, but it is also a reminder of the limitations of this self-made value. When the Kim family’s home floods – a biblical torrent that sends sewage streaming from the toilet and destroys their miserable belongings – the rock endures.

Homeless and sodden, the family lie on the floor of a gym, and Ki-woo embraces the stone. “Why are you hugging that thing?” his father asks. “It wants to be with me,” his son replies. “It’s true. It keeps following me. I knew it was a sign when Min-hyuk gave it to me. A symbolic gift …” He cradles it tightly. He lugs it to an anxiety-inducing party, where he will be forced to act the part of the urbane tutor; things end badly. At moments of hellish drama and chaos, the rock re-emerges, like a body that won’t sink.

Parasite is set in the present day, an economically turbulent era in which value and product feel cleaved from one another. In London, residential planning permission on a piece of land can see its value rocket from £21,000 to £1.95m a hectare. The bitcoin boom saw billionaires created overnight, insanely rich off the back of an intangible currency. Amid this economic chaos, faith in the promise of stones and jewels makes abrupt sense. It doesn’t matter if their value is real, imagined or just longed-for: the allure is undeniable.

Bong is sometimes deliberately, deliciously obvious. When Ki-woo is presented with the rock, he coos: “It’s so metaphorical.” In the final scenes, we see the origins of the viewing stone, as a pair of hands pluck the rock from a pristine stream. We hear Ki-woo’s message to his estranged, imprisoned father: he is making “a long-term plan … I’m going to make a lot of money.” The viewer watches, knowing this rock was used to split Ki-woo’s head open.

The film’s enormous sadness lies in the determination of some people never to give up the dream of crossing the gap between rich and poor, the haves and have-nots. In doing so, they put their shoulder to the sisyphean task of pushing the rock up the hill, and it crushes them, as it does Parasite’s Kim family.