[ATM] Will Alum Oxide fine grind quartz blank?

[Anthony Stillman]

>Will Alum Oxide fine grind quartz blank?

My experience with quartz, and by quartz I mean fused silica, is that grits behave on it compared to pyrex (borosilicate) as if they are one and half to two grits finer.  60 grit behaves like 100, 80 like 220, 600 like 9 micron and so on. Also the grit breaks down much more quickly.  What would be a one minute wet on pyrex might be only 10 seconds on quartz. Since mostly alpha corundum is used for fine grinding it can seem like it isn't doing anything.  Incidentally di-aluminum tri-oxide is harder than silicon carbide.  It's a 9 as opposed to 8 to 8.5 on the mohs hardness scale.  Fused silica is nearly a 7.  The mohs hardness scale is pretty linear except for diamond (10) which is 50 to 100 times harder than saphire(9) depending on the diamond's origin.

I've tried mirror grinding with fine diamond powder, scratch city.

Anthony