So ever since we’ve seen the murals of the Diamonds on the moon base in It Could’ve Been Great, I’ve been thinking a lot about how each one could represent their roles. (Not including Pink Diamond because we didn’t see her mural).
Let’s start with
our Giraffe Overlord Yellow Diamond. She’s seen with planets/stars directly in the palms of her hands, and she’s looking out into space at other planets. It’s like the fate of these other planets in her sight rest in her hands. Peridot did call her a “decider” in Message Received, so maybe she decides which planets are of interest to Homeworld; which ones to invade and use to their desire to expand their empire.
Now, the elegant Blue Diamond. The planets in her grasp are all in a neat, controlled line. If The Answer is indicative of anything, we can infer that she must be a diplomatic gem. She probably maintains order among the gem-controlled planets.
Lastly, the elusive and mysterious White Diamond. We haven’t seen her at all in the show yet, so speculation around her is most likely to be untrue. But her mural could be giving some major clues. What pops out first is the circle of light her hands are surrounding. This could be symbolic of the immense amount of power she holds. And maybe she’s more powerful than Yellow and Blue (which very likely could be the case since her symbol is always above the other diamonds).
Also, the planets in the mural wrap around the top of her head, as if all planets are within her sphere of influence. I’m thinking she really could hold the most power among the diamonds.