You're writing fiction, make it up :-) Off the top of my head, metals and alloys crystallize differently in microgravity. It's also easy to make perfect spheres. I'm sure that googling microgravity technology will give you further leads.
From what I've seen the ISS is doing very interesting work on plasma physics in space due to having free high-vacuum available and the ability to inject highly-visible tracer particles into a plasma chamber which don't settle out, this also allowing interesting mixed particulate/plasma states.
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