From what I read somewhere the MC3000 MK II uses the same body as the original MC300, so I went back to that review to gather some construction info. That info tracks what the owners manual says.
"The magnet material was changed to a more powerful material called neodymium (it used to be an alloy of samarium and cobalt) and moved closer to the coils, which doubled the cartridge's output. And because the stronger magnetic field might have an adverse effect on motions of the original aluminum armature (footnote 1), the 3000's armature is made of carbon fiber. Even the outer casing material was changed, from aluminum to aluminum oxide. This sintered (fired) ceramic compound has a hardness of 9 Mohs, 1 unit below that of a diamond's 10. The harder a material, the higher its natural resonating frequency; the new case is an attempt to get this out beyond the audible range without having to resort to a diamond case."
So aluminum oxide is really hard stuff. They also make cantilevers out of it also as I recall. Very interesting stuff, thanks so much for sharing your knowledge.
"The magnet material was changed to a more powerful material called neodymium (it used to be an alloy of samarium and cobalt) and moved closer to the coils, which doubled the cartridge's output. And because the stronger magnetic field might have an adverse effect on motions of the original aluminum armature (footnote 1), the 3000's armature is made of carbon fiber. Even the outer casing material was changed, from aluminum to aluminum oxide. This sintered (fired) ceramic compound has a hardness of 9 Mohs, 1 unit below that of a diamond's 10. The harder a material, the higher its natural resonating frequency; the new case is an attempt to get this out beyond the audible range without having to resort to a diamond case."
So aluminum oxide is really hard stuff. They also make cantilevers out of it also as I recall. Very interesting stuff, thanks so much for sharing your knowledge.