tbh the “which one is she?” joke really felt like the crew taking a nod at/acknowledging the fact amethyst and lapis have had the least interaction out of any of the main gems.
and then ofc the two actually have a surprising amount in common for a pair who’ve never really interacted on screen (jasper issues, toilet humour, implied to be sharing manga or at least reading the same one, interest in garbage, are the two gems peridot would prob consider herself closest with…)
keep in mind the show tends to be v good at following up this sort of thing.