I used to think 'ice' too, but think about this: the sun is basically a point-source of lighting for Ceres; and yet the bright spot can be seen at various angle

I used to think 'ice' too, but think about this: the sun is basically a point-source of lighting for Ceres; and yet the bright spot can be seen at various angles. Now, it is possible that it's a huge jaggedy piece of, such that it reflects sunlight at a wide range of angles; but what if it isn't? :-)