Your whetstone will most likely be double-sided with a coarse and a fine grit. The grit is determined by the number of sand-like particles in the stone. The coarse grit will have fewer particles, whereas the finer grit will have more grains. Both sides are utilized to effectively sharpen a blade. The coarse grit, usually a deeper color; red or gray, will pre-sharpen the blade and remove any burrs or discrepancies in the blade. The finer grit is then used to hone and polish the blade, creating a finished edge.
Sharpening stone/whetstones. Just as there are dozens of different ways to sharpen a knife, there are dozens of different sharpening stones. There are Japanese water stones, stones with diamond encrusted surfaces, and stones with different grades of grit. Again, choosing a stone is a matter of function and preference. Play around with different kinds of stones to find the one that gives you the results you’re looking for.
If you’re sharpening high quality knives, you probably don’t want to use a cheapo sharpening stone. But if you’re just getting started with sharpening your pocket knife, there’s no need to get too fancy right off the bat. You can find a sharpening stone at most hardware stores for about $10. This one is very similar to the one I use. Nothing fancy. Most basic sharpening stones come with two sides: a rough grit and a fine grit. The finer the grit, the finer or sharper you can get your blade. You usually start off sharpening on the rough grit and then finish sharpening it on the finer grit.