What is an Aluminium Oxide Stone Used For?

We sell a wide variety of mounted aluminium oxide stones that can be used with either our Apex or Professional model sharpening systems. These stones are very inexpensive compared to the high cost of other stones, and are well suited for beginners.

Often referred to as corundum (in fused form) or aloxite in the materials science community, this is an excellent abrasive. With a hardness of 9 on the Mohs scale of mineral hardness (just below diamond) it is widely used in industrial applications as a less expensive alternative to diamond. It is also a key ingredient in many types of sandpaper and a major component of the powdery abrasive called cue tip chalk used in billiards.

It is easy to sharpen steel with an abrasive like an aluminium oxide stone, and this type of stone does very well on most kitchen knives, carpentry tools and hunting/EDC knives. It does not do as well with some ‘high carbon’ steels that contain significant amounts of hard carbides, such as the chromium and vanadium carbides in D2 steel. These carbides add a great deal of wear resistance to the steel and will significantly slow grinding on an aluminum oxide stone, but a SiC stone or even a diamond hone will easily grind these more complex steels.

As an abrasive, the Aluminium Oxide stone will naturally wear over time, and this is why we recommend the use of a special “Honey” oil to lubricate your stone while you work. This will help minimize the amount of friction between your blade and the stone, as well as keep your stones from becoming too dry and losing their abrasiveness. Alternatively, you can use something like WD-40 or just soak your stones in water for a few minutes after each sharpening session to minimize the rate of wear.