>>113508079My take on it is that they're a semi-computerized form of life that originally was all-light, possibly without a Gem. They were some sorta predators, maybe, that'd explain the hierarchy built into them by nature, it seems (even rebellous gems obey a Diamond, in essense) and their animalistic behaviors.
Some of their present traits are leftover original stuff: the strict hierarchy to the tune of White's folding to Pink once Steven slapped her down, essentially shown that he's superior to her, the scampering around Peridot does, the sharp teeth, maybe shapeshifting, essentially the next step to a cat's hair standing up to make it seem bigger.
Some of their traits are very blatantly not normal for them. They have to force themselves to abide by them and keep them. That being, lack of emotions, just intelligence in general (the smarter a gem is, the better it is at managing its emotions, which is critical for such a volatile species), the artificial society and artificial technology, and by artificial I mean clearly not naturally-developing.
I pray to god at least the artbook will have something on their origin, if the show won't.