Dan,(posted 8244 days ago)Amidol (2,4-Diaminophenol dihydrochloride) is colorless when ultra- pure. It quickly oxidizes and takes on an increasingly dark color. A very small amount of oxidation can color the material intensely, so it's hard to say much about purity just from color. I buy amidol from Artcraft Chemicals and get a light gray fluffy powder. Check out Artcraft’s price (www.artcraftchemicals.com), it's the best I’ve seen.
I've never seen red colored amidol crystals.