Aww, but at least the Earth gems are remembering their siblings and their old feelings towards them... Whatever it was that triggered that, I'm happy about it. :3
@Kagamimocchi
But we saw it when Phos forced Adamant to pray. This is the closest the Lunarians have ever been to their objective. I've read theories that the reason Adamant doesn't pray is because it'd cause everyone, including the gems, to disappear.
By defect, it's not meant Adamant can't pray. It's just, he can't choose to send only Lunarian to nirvana. All living beings will be affected by it, so yeah, all the gems will disappear too.