How to differ Alnico from Ceramic?

[GianGian]

I have an old bass, like 6 years old, that has a huge bottom end and some nice highs. The pick up is as far as possible from the strings and even then, when I pluck too hard, the output saturates, even before getting to the amp. Another bass that I have, has a softer bottom end, softer highs, a thinner tone on general, but is much stronger at the mid frequencies. I don't notice any difference in general volume between the two, altough the low end on the older bass is way louder than the high notes. They are both Jazzes copies. Can I know what are the magnets just by this information?
P.S.: The poles on the old one are almost completely "black" from oxidation.

[GlennW]

There are no ceramic rod magnets (I think), so if your pickups are the kind without bar magnets on the bottom (unlike MIM and SX JB pickups which do have ceramic bars on the bottom) they're likely alnico. You can check the individual poles with an ohmmeter; alnico conducts, ceramic doesn't.

[GianGian]

Originally Posted by GlennW

There are no ceramic rod magnets (I think), so if your pickups are the kind without bar magnets on the bottom (unlike MIM and SX JB pickups which do have ceramic bars on the bottom) they're likely alnico. You can check the individual poles with an ohmmeter; alnico conducts, ceramic doesn't.

I remember removing one pick up once and it had that big silver coloured magnetic thing on the bottom. It is probably alnico then. The ones on the other bass don't seen to make that noise when the string touches the poles. I think it is ceramic as it sounds so different from the other.