Polishing jadeite is not one operation. It is eleven, and each one exists to remove the scratches left by the one before it.
The first wheels are coarse enough to feel like sandpaper through the stone. By the sixth the surface already looks finished to anyone who has not done it before. It is not. Hold it against a raking light and the whole face is a haze of parallel scratches from the previous grade. Every subsequent wheel is spent erasing evidence.
The last stage is not a wheel at all but leather charged with a fine oxide paste, worked by hand. This is where jadeite stops looking like glass and starts looking wet. The difference between a competent polish and a very good one is roughly two hours per piece and is visible from across a room.
Water runs continuously through all of it. Jadeite is tough rather than hard, and heat is what cracks it.