found a pet store in Kuching that sells the stone. But this is not easy to cut!
May I know how did you cut it? I used diamond costed cutting wheel. Need sometime for practice, I failed the whole piece of stone for the first time... And what type of air stone you'd found?(mind to share the pic?) Grey color? Be sure it's an aluminium oxide(Al2O3). Torch it hot red up to 30 seconds, if it crumbles or has smell of burning stuff, don't use it.
Edit: Don't get the rough one, look for finer one, fine grit like 80 - 100 grit sandpaper. Rough one is difficult to cut or grind, the grains will tend to fall off while grinding it.