These are the exciting colors of scales I have lying around at the moment.

At left is blackened stainless steel. It is a slightly irregular and slightly matte deep black. The black doesn't scratch unless you try really hard (as in rub it on concrete vigorously for a number of seconds).

At bottom is standard stainless steel.

At right is yellow brass. It starts out a bright gold color, and slowly ages to a darker yellow, but can be cleaned with a brass cleaner.

At top is heat-colored nickel plated mild steel. The heating causes an oxidation layer to build on the surface, which gives it beautiful color. Individual scales in a batch range from a pale green to deep gold-orange to red to a transparent blue to a royal purple. They are irregular and mottled sometimes, and appear iridescent. I fell in love with them as soon as I saw them.

The color on the nickel scales, being an oxidation layer, has a tendency to fade when you rub the scales; the oils on your fingers screws up the oxidation. For this reason, I was sadly reluctant to use these scales for anything. But I just discovered that the colors are trivial to bring back--you just wash the scales with soap and water, the oils wash away, and the colors return completely. Nobody has any idea how happy this makes me.

Anyway, these are the colors I have at my disposal right now. I need to make something of the heat-colored ones now that I know they actually work.

(Also, since I know someone will ask, I get these scales from www.theringlord.com)

EDITS: The Ring Lord stopped making the heat-colored nickel ones a while back, but I still have a bit of them, and I've been told by the person who runs the company that if I ask he would specially make some for me. (Though I would only want to do this if I got a large commission that wanted to use these scales.)
They also recently stopped making the yellow brass. They will replace it with bronze after a while, they say, but I don't know how the bronze will look.