The Quartz Gun is an aggregate of quartz.
It took on the shape of what would seem like a giant flying board. It sports a mouth that swallows additional quartz, presumably to enhance its power. It is a gun capable of destroying Secrets but in doing, creates a new timeline by erasing or altering the present as when Ao fired the gun for the first time, history was rewritten as in the new reality, Maggie Kwan, Chloe McCaffrey and Maeve McCaffrey never joined Generation Bleu which would led to the creation of Team Goldilocks.
The memories from the "previous" world can only be detected by a few people, who might include:
Quartz gun being fired from low orbit