Diamond stones and other stones used for less aggressive actions that do not require the file such as: burrs (grinding stones) and polishing the edges (diamonds).
--------------
DIAMONDS: used to polish the edges. There are different brands and measures, but especially distinguished by the density of diamond grains per cm^2. A denser, finer grinding, but less thicker the grain. Is not always adequate to start by the finest, you should start by grinding coarser and work down.
--------------
STONES: used for burrs and to clean the edges.