I’m a diamond cutter and stone polisher and deal with diamond powder
regularly. We use a slurry of powder and olive oil and I use this on
leather also. Olive oil acts a a lubricant and gets more viscous with
time allowed to air. My wheel spins at a high rate of speed and the
diamond slurry applied with finger or small piece of leather stays
put but movable. So there might be times when you want powder slurry
to move a lot like with mineral oil or get stickier with olive oil. I
don’t use much oil to powder mix…just thick like thin peanut butter.
Hope this help your situation.
Ron