Monster Reunion finally gave us insight on the nature of corrupted gems. I think many of us had gotten the jist of it for a while, but corrupted gems are affected by their mental state, not their physical state. This especially explains why neither Rose Quartz or Steven could completely “heal” them.We also learned that the giant light seen in Lapis Lazuli’s flashback in “Same Old World” may very well have caused the corruption to occur, which many have theorized already. The process seems vague, but we know it was a direct attack from the Diamonds. Isn’t it interesting that Steven described it the sound it made as a “song”? Also isn’t it also interesting that what helped jogged Centipeedle’s memory was Steven singing the “Chaps” theme song? Music may have something to how the gems were corrupted (and it could help reverse the effects?). Corrupted gems also can’t seem to use gem tech like warp pads. This may be the main reason why the Diamonds used it in the first place: it was to prevent survivors from leaving the planet (and also perhaps they’re pretty sore losers. Sure, the Crystal Gems have their planet, but they won’t be able to enjoy it). One final thing to note is that gems of the same species will turn into the same gem monster.
But now the question is, how were Lapis and Amethyst not effected? While Amethyst may not have emerged, she was certainly taking her time in the ground. (she spent an extra 500 years in there from when the injectors inserted her gem). I may have a theory to that: being stuck inside an object may have prevented corruption. Amethyst was busy gestating inside the ground, Lapis was stuck inside the mirror, and Rose Quartz shielded herself as well as Pearl and Garnet from the bomb. Giving them a kind of barrier could have saved them. The problem with this theory is that some gems stored in objects were already corrupted (like the oddly white, diamond shaped gem from the obelisk). That is, unless, those gems were placed inside objects after they were effected (or perhaps they were test subjects). I also thought it could be due to gems losing their physical form could be in a state of inactivity or unconsciousness, but the barrier theory seems more likely.
In any case, for those who have gemsonas on Earth, the information given from today’s episode should be noted.
On an unrelated note, a new gem may have been subtly introduced.
Some people have theorized the gem is Citrine because of how Centipeedle drew her with a gold colored crayon, how quartz gems seem to have a high status on Homeworld, and the fact the gem has a rectangular/baguette cut (as Citrines are commonly cut this way). I disagree. It’s not so much the gem cut, but how the gem was drawn. Quartz gems have very jagged hair and we have seen this time and time again in various flashbacks and depictions. Centipeedle’s drawings were no exception.
(I’m also quite curious of what some of these other gems depicted here are!) Rose Quartz is the only one that doesn’t have the standard jagged hair that we have seen quartz gems have, but she still shares some similar traits (the hairline and the curled strands of hair). I think the commander is an entirely new gem we have yet to see. I’ll take a jab at guessing what gem the commander is based on. I think she may be a Topaz (perhaps even Imperial Topaz). In their raw form, Topazes are long and cylinder like, something quite similar to the gem cut on her chest. Metaphysically, topazes are often considered crystals of leaders, both representing its virtues and help improve leadership skills.
Not to say it can’t be Citrine, but there’s a lot of evidence saying otherwise. Heliodor/Golden Beryl could be another guess too!