The Arnold site actually gives some simple characterization procedures using only an oscilloscope, signal geneartor, and a few passive components.
As for the part I have, the color, partial part number that corresponds closely to the measured size, and observed inductance point to the fact the the "ferrite" is probably a Molypermalloy Powder (MPP) toroid made by Magnetics. In fact, the calculated turns for the measured inductance of my test coil is a little too close. I intended 400 turns, the calculated value is 395 turns. I can't count that accurately! John