First question! I'm excited to see if anyone can help me. Any missteps are unintentional, but feel free to tell me so that I may learn.
So, I've recently started brainstorming over a possible story, and I was wondering if someone might be able to lend me a hand with a bit of worldbuilding. The world where the story takes place is a classic high-fantasy setting. However, there is a sci-fi element to it that is giving me some trouble.
Imagine an alien spaceship that crashes on the high-fantasy planet. Imagine that the people who live on said high-fantasy planet eventually scavenge the spaceship and find out that the alien metal is great for forging magical items of all kinds.
Now, imagine this metal glows a pale blue when pieces of itself are near each other. I could chalk it up to magic and be done with it, but seeing how this is a plot device wrought from sci-fi elements, I would like to have a more or less science-based answer for why the metal reacts to itself.
The way I thought about it, the starship itself doesn't glow when it's in one piece, but after being dismantled, its largest chunk begins glowing and doesn't stop glowing, sort of like a beacon for all its smaller pieces, which in turn glow brighter the closer they get to a larger chunk. Chunks of roughly the same size have a faint glow that is sort of noticeable in the dark. Larger chunks have a greater reach, making smaller chunks glow from many metres or even kilometres away. I'm willing to edit these details to better accommodate your answers.
I've considered some sort of nanotechnology being responsible rather than the glow being a naturally-occurring phenomenon—it's an alien artefact from a spacefaring species, after all. I've also looked into bioluminescence and incandescence and pyrophoric properties, but nothing quite hits the mark. If what I'm asking is at all possible, please do tell!
EDIT1: The sci-fi explanation will be required further down the line for the plot, which is why I'm trying to figure it out. People from the high-fantasy world will consider the metal's glowing to be magical in nature until then.
EDIT2: It doesn't have to be metal! It can be any material that can be turned into the usual items you see in fantasy worlds—weapons, armours, cooking utensils, amulets, light fixtures, clockwork mechanisms, fancy furniture, and the like.
EDIT3: I would rather not have the metal be sentient.