bummer that means i would have been done with sanding 3 weeks ago
o well the extra steps to 1500 kept me busy for a while....wher were u before i started....DOH
and for your question i dont think the higher grits i.e 400-2000 are made with aluminum oxide i could be wrong, but caswell sell's all kinds of sandpaper below is the link!
http://www.caswellplating.com/buffs/wetanddry.htm