The general rule is Brass = Yellow, Bronze = Reddish, . . . but there are instances where you simply can't tell. Chips can be an indication, but I've had brass curl and chip, and bronze chip (SAE660) and curl (C510). I usually know my materials by what I've ordered, and then keep them separated, but lacking that I usually go by color. I have had supplies of C510 (phosphor bronze) from different sources which behaved entirely differently from each other so that neither their color nor a machining test would have told me they were the same. My suspicion of course was that they were not the same alloy, and the supplier made a mistake.
