That's the color in my experience.

Last time I made Ferric Oxalate, I used a 600ml beaker with 25ml water, 6.7g B&S Ferric Ox, about 1g EDTA and a 1000ml water bath at 150 degrees. I swirled the solution around in the bottom of the beaker, submerged in the hot water. Went into solution in about 15 minutes. Easiest time I've ever had with this step.
Neal