Thank you! And a happy new year to you too!
I'm sorry, but it seems my idea might have to wait until tomorrow or Monday. My mom is having me clean my room so we can put the old computer in there. It is quite a chore to move things into areas that are both accessible and leave me with the ability to find them.
I currently have the beginning of my idea in a draft post, but to be short about it, it involves an island that was only recently discovered within the last century or so. It would lie just beyond the known skies at a significantly lower altitude than most of the other islands in Cerulea. The cause for this would be the former residents of that island (now barren except for ruined buildings dormant machinery) tapped the core cerulite for their island without realizing its significant role in the lives of everything living upon their island. They would have had no knowledge of magic, or at least of letting cerulite regenerate after use, and mainly used cerulite for operating machinery, completely draining the cerulite used with no hope of regeneration. Naturally, there would have been disputes over remaining resources as crops began to fail and the island started to sink. The residents had died out either by war or by starvation and disease (or a combination) before half of the island's core cerulite was mined, which would explain why it is still in the sky even at this altitude.
Much of the machinery on the island will have been salvaged for parts over the years by small groups of people who have discovered the island on their own, but there would be enough left to suggest that the earlier residents of the island hadn't thought to turning their developments in technology towards flying.
There are some problems with this, like "why didn't they think to fly to another island?" and I really don't want to explain that away with the answer "in their previous world, their species had never looked to the sky as a frontier to be explored" or anything like that, so I'm still thinking about this and how to put it into words...unless I did just there. Actually, this tells more than my draft version so I guess I'll put the idea here as it is and then we can work out details as we go. (I tend to not delete previous writings in a post so I can look at my thought processes when it comes to these kinds of things, so please forgive my seeming wishy-washy in this post)