Flashing red-brown crystal pieces or sand-like, melting point 118 ~ 118.5 ℃. Soluble in water was yellow orange, soluble in alcohol and soluble fiber element, slightly soluble in acetone, insoluble in benzene. Case of concentrated sulfuric acid yellow, diluted orange; case of nitric acid was orange. Its solution plus sodium hydroxide solution is generated red-brown precipitate in tannin mordant dyeing of cotton fiber was prime on the yellow orange, in the tungsten light, more bright.