What is the significance of the rock?

In Parasite (2019), the decorative rock given to the Kim family by Min is described in the English subtitles as a "scholar's rock," and that it was said to "bring material wealth to families." Indeed, shortly after the Kim family got the rock, they got material wealth from their new jobs.

I don't quite understand the significance or symbolism of how it was used. After the flood, Ki-woo was hugging the rock and said that "it [the rock] keeps clinging to me." Ki-woo attempted to use it as a weapon to attack or kill Moon-gwang (former housekeeper) and Geun-se (Moon-gwang's husband), but this plan backfired.

Near the film's conclusion, Ki-woo placed the rock in a stream. This was after they've already lost their material wealth: their belongings (to the flood) and their jobs.

What is the rock's significance? What does it symbolize? Is there a Korean cultural significance to scholar's rocks that is being referenced in the film?

The director, Bong Joon-ho, did an interview where he lightly discusses the rocks significance. He mentions the rock as a symbol, but he does not specify what it is a symbol for.

From my own viewing, the rock is a metaphor for the family's employment.

The family receives the rock as a gift from Min along with a gift of the first tutoring job, and just like with the job it is initially a great blessing.

Later during the storm, the jobs have begun to unravel. They have come in conflict with another family over the right to serve the rich family, and now the rock has become a burden that Ki-woo has to carry and we see it literally weighing down on him in the gym. The two families fighting comes to a conclusion when Ki-woo attempts to murder the man in the basement with the stone, to secure his families prosperity, but gets crushed by the stone instead.

Finally in this metaphor, returning the stone can be read as losing the job both literally and mentally, but it is also in most stories how you break a curse.