>>149821556
>The series never addressed who created the gems in the first place
Yes they fucking did. The Diamonds can impregnate living soil with their sweat. This fluid was stored in the injectors they use, and gems emerge after enough pressure. As for the origins of the Diamonds, they likely emerged from asteroids (which also happens in real life). The heat and pressure released from the impact of an asteroid causes carbon atoms to crystallize, resulting in Diamond being made.
The explanation you are looking for is just too straightforward for your taste.