Non-Activated star color metals (Copper, Cadmium, Emeril, Indium) can also easily be refined to make a lot more of themselves.
Say you need more Copper… Split what you have in half, refine half into Chromatic Metal, then combine this with the remaining Copper to produce more Copper then you started with. And if it’s Chromatic Metal you need, refine some of it again. Like @Polyphemus suggests, higher colors (see the order above) produce better ratios of Chromatic Metal.
I believe the Activated versions of the star metals produce the same amount of Chromatic Metal as the non-Activated, just faster, but they can’t be expanded the same way.