A lot of people were right; Peridot is smol and adorable without her limb enhancers and Amethyst deserves a medal for throwing them away.
There is only one Cluster.
We have not seen the Cluster yet.
Steven polishes his gem as part of his morning/nightly routine.
Steven keeps an unframed picture of Connie sitting out in the open above his bed.
Peridot probably doesn’t actually know how to summon her tool, or just doesn’t have one (she probably would have used it to pummel Steven with if she did).
The Cluster is going to hatch soon and Peridot is scared shitless of it.
“Harvesting” is something that happens on Homeworld and it’s either unpleasant, lethal, or both.
What can we extrapolate?
The thing that Peridot used to disable her Flask Robonoids in Warp Tour was probably another of her inventions that was just stored in her gem. In lieu of any official name I’m going to call this device a Blast Robonoid.
The Cluster will probably be the largest and most powerful creature in the show thus far, possibly even rivaling Lapis’ magical strength with its physical strength.
There are two artifices shown in the show so far that the Crystal Gems may be forced to resort to using to defeat the Cluster: The Shooting Star and The Geode. Pearl said in Winter Forecast that “the Shooting Star could explode forever in Warp Space”, and it was shown that the blast of the Shooting Star could easily destroy the entire temple, but whether or not it could penetrate Rose’s shield remains to be seen. Pearl also explains in The Guest that the Geode would vaporize their bodies (and presumably their gems) if the storm inside were released. With Steven’s bubble, it’s possible that the gems could survive a brief blast of the storm, using it to destroy the Cluster, before sending Greg or Connie in to contain it again.
Regardless of proportion or body shape (given that gems choose the way they physically manifest), it’s actually probable that Peridot is not only younger than Amethyst, but also less developmentally advanced despite her obvious education. She is prone to panic, temper tantrums, petty mimicry, and, so far as we know, is unable to summon her tool from her gem—all indications that she may be the closest thing we’ve seen to the gem equivalent of a child. Even if she is a gem child though, she’s likely several hundred, if not more than a thousand years old.
Steven fucking eats it at like thirty miles an hour flipping into the basement and makes no comment on pain (despite obviously feeling at least some), but comments that Peridot’s slap hurts a lot. We laugh because she seems impotent and tiny but she’s still a gem, and that slap probably would’ve broken any human’s nose. She may be weak compared to Steven, and especially the other gems, bust Steven’s lifted fully grown adults and ripped part of an arcade cabinet off to beat the rest of it to shit with before; he is much tougher and more resilient than an ordinary human. Consider that before you write or draw Peridot slapping ineffectually at Lars for calling her “pipsqueak”.