Description: When it comes to polishing and picking compounds two things matter: grain size, and particle type.
Pre-polish is equivalent to approximately 1000g
Final Polish is Equivalent to approximately 3000g
Aluminum oxide, as a particle type rounds over on its edges, which is why its so good for buffing. the particle rounds over just like stones do, which is why: When the pre-polish is done its week in the tumbler, it is almost equivalent to the pre-pol. Remember- everything is wearing down in that barrel, not just the stones. Even the barrel walls are wearing down over time.
Use: Aluminum Oxide is predominantly meant for tumblers. They can also be used to charge felt or leather buffs. Aluminum Oxide is the most economical polishing compound and great for pretty much any kind of stone. Some particle types are better for specific mineral families, but aluminum oxide is good for just about any 6 or harder on the Mohs.
Re-use: This is also a great option for vibratory laps, and a lot of companies wont tell you, but you can reuse the final and prepol grit stages in a tumbler. cut it with about 50% new powder though.