Put a kind of life-like being that "convert" natural resources in gemstones.

Something similar to the sandworm of Dune or the Tiberium from Command and Conquer series.

You could start your story saying that the planet many millennia ago was full of natural resources. Then for some "unknown" reason (here subters your creativity) a genetically modified creature started to assimilate the natural resources and releasing gems as junk without control. This condition quickly turns the planet into a deserted land full of gems.....

Put a kind of life-like being that "convert" natural resources in gemstones.

Something similar to the sandworm of Dune or the Tiberium from Command and Conquer series.

You could start your story saying that the planet many millennia ago was full of natural resources. Then for some "unknown" reason (here subters your creativity) a genetically modified creature started to assimilate the natural resources and releasing gems as processing waste without control. This condition quickly turns the planet into a deserted land full of gems.....