The Rainbow Quartz fusion, together with the revelations of A Single Pale Rose, introduces a massive continuity error in the plot/lore of this series, and it baffles me that no one else has seemed to notice.
At the moment Pearl and Rose's bodies convert into light to form Rainbow Quartz in We Need to Talk, Rose's gemstone becomes plainly visible from various angles to both the viewer and all characters witnessing the fusion (Greg, Garnet, Amethyst, and also Steven viewing via the recording). Knowing what we know now, there is no reason why Rose’s gem should have appeared as anything but a large pointed pink diamond, but instead we only see a standard egg-shaped one with rounded edges. How?
Even if you write this off as a minor oversight that might deserve forgiveness for how it’s from a scene that came long before the pink diamond revelation was decided on, the same issue arises with the fusion of Smoky Quartz much later in the series. In Know Your Fusion, Steven and Amethyst fuse right in front of Garnet, meaning that for a brief moment, Steven’s gemstone should have become fully visible to her, pointy end and all. Come to think of it, in Mindful Education, Steven again fuses multiple times just inches away from Garnet’s face. How did any of this happen without Steven’s true gem identity becoming apparent to those in his surroundings? I would be very interested in hearing any proposed justifications for this, because it has been eating away at me for days.