Shoutout to waffler21 for this idea!!!
We all know The Diamonds are responsible for the corruption of Centipeedle and many other gems. What this is the result of not having Pink Diamond? I believe that when all 4 Diamonds fuse together and they sing they can shatter any gem much like how a high note can shatter glass. But since Pink Diamond isnt in the fusion then all the remaining Diamonds can do is corrupt gems when they fuse together and sing.
Let me know what you think in the comments!!!