Not sure I understand the issue completely, but I've left out Dan's translucent and black hard Arkansas oil-stones out with standing oil on the surface, and in returning later, some of the oil would be absorbed. From this, I would be inclined to think they are somewhat porous; and with water, I would think the effect would take place more quickly. Vermont slate, by way of comparison, is not porous at all. Standing oil will stay there for days. Maybe that's why the latter works well for roofing purposes. Too bad your metal box isn't a sharpening stone. It looks great.