[made2hack]

Well done mate impressive, masterpiece study it is.
I appreciate it. Alumina test made me surprised that I never imagibed such thing before. But it seems brittle though. Allumina is the second hardest following diamond yea?

Hi, yeah it is at the top in terms of hardness, but you can go harder (think Carbides such as Silicon or Titanium Carbide. Although, I don't know if it matters in our case, since I am not trying to cut or sand another surface. I just want an epoxy composite to act as a vibration damper.

So in an epoxy matrix, it is no more brittle than the epoxy granite or quartz granite, unless you try to break it with a hammer.

However, as a ceramic (think Aluminium Oxide crucible), I imagine it is quite brittle (such as porcelain, maybe even more so). Then again, I guess a silicon oxide ceramic or titanium oxide ceramic would also break as easily.

The problem is that I don't think many companies sell Aluminium Oxide as stone or pebbles. You generally find it as a fine powder, usually purified for special use. Or sometimes you might find it as a larger particle for sand blasting.

Whereas Quartz (Silicon Oxide) is readily sold everywhere and is quite cheap. You can find it at the hardware store as silicia sand and at the pet store as aquarium quartz decoration.