Your experiment reminds me of some that were done with the Spyderco hones using various slurries. I used a natural nagura and some garnet. In both cases the hone functioned as a substrate to hold the slurry abrasive. Robert Williams did the same with diamond paste/powder. I would suspect that any number of different rocks/hones would function the same way as long as they are relatively hard. Essentially what is being done is to use various materials as a substrate to hold an abrasive. Historically leather, linen/canvas/felt, wood and now stone have been used. The manmade hones and materials are next.

We do have a lot of tools that we can use!