Ever since 'Same Old World', there have been questions and theories about that flash of light that Lapis described in her flashback story. Centipeetle described the same thing. Greg Universe even mentioned it in 'The Return'. "Gems were destroyed, people too... In the end, your mother could only save a handful of her closest friends." And now we're finally figuring out just what happened at the end of the war. There is a great comparison video for Lapis and Centipeetle's experiences, as well as a couple of theories about the Diamond weapon that nuked Earth. Some very interesting stuff below the break!
The Gem Destabilizers are tuning forks.
Steven says, "A sound? A song?" in response to the bright light that caused gem corruption on Earth.
Sound must play a huge role in weakening/corruption of gems, but Rose's shield has been shown to let out vibrations that caused Lapis' water clones to destabalize.
Music could be one of the keys to bringing back corrupted gems.
The Diamonds have clearly figured out how to weaponize sound against their own kind, but Peridot didn't know what music was. Homeworld must have either a warped idea of music, or it doesn't exist at all.
Powers based on songs would make a whole lot of sense to the world and why Steven (and the other gems) are compelled to randomly sing. Peridot naturally being able to pick up the mechanics of notes and voice pitch rather instantly would also make more sense if gems are predispositioned to have vocal based powers rather then “lmao peri is so smart.”
Jasper yelling for Sapphire to stop singing in 'Jail Break' could have been more of an aggressive self preservation rather then annoyance, since she was apart of the war on Earth, she likely saw the effects of the Diamonds’ song first hand.
Sapphire was singing as a message to Ruby/ the Crystal gems to find her. (She has future vision so she saw that Ruby and Steven would find her if she did this.) Jasper didn’t punch a wall and yell at Sapphire to stop singing just to be mean. She was specifically cutting off Sapphire’s mode of communicating with the others.
Songs could also have codes in them, think of that.