What are the different types of sharpening stones?
There are many types of sharpening stones available, each with its own unique qualities and advantages. Whether you’re using natural stones, synthetic stones, or diamond sharpening stones, the best choice largely depends on the type of knife you're sharpening and your personal preferences.
Natural sharpening stones are prized for their ability to create incredibly sharp edges and beautiful finishes, but they come with a few challenges. These stones are generally more expensive than mass-produced alternatives, and their lack of standardized grit sizes, hardness, and cutting speeds means that experience is needed to select the right stone for a specific knife. Natural stones wear down unevenly depending on their composition and where they were mined (not to mention your specific sharpening style), so they must be flattened periodically to maintain consistent performance. However, many sharpeners value natural stones for the fine, crisp edge they can produce, as well as the smooth, polished finish that’s hard to replicate with other types of stones.
Synthetic sharpening stones, on the other hand, are more affordable and widely available. They have a more consistent grit scale, similar to that of sandpaper: lower numbers represent coarser grits, while higher numbers correspond to finer grits. Similarly to natural stones, synthetic stones also wear down over time and must be flattened to ensure a smooth, even sharpening surface. These stones are easy to use and maintain, making them an excellent choice for most home cooks and casual sharpeners.
If you’re sharpening knives in a home kitchen, a set of mid-range synthetic stones is often the best choice. They offer a great balance of price, ease of use, and performance.
Diamond sharpening stones are another option, and while they tend to be more expensive than other types of synthetic stones, they are known for their durability. They have a calibrated grit, and because they don’t wear down in the same way that natural or synthetic stones do, they can last much longer. However, over time, the diamonds themselves may begin to loosen or fall off the steel or aluminum backing plate. Despite this, they require less upkeep compared to other types of stones, making them a good choice for those willing to invest in a longer-lasting tool without the need to flatten.
Many sharpeners, myself included, use a combination of natural and synthetic stones. While natural stones are often more expensive, their performance on finer grits can be well worth the investment. For coarser grits, synthetic stones work just as well—if not better—because they offer similar results at a fraction of the cost. I prefer to use synthetic stones for lower grits to establish the edge profile, and then finish with a series of natural stones for a refined, polished edge.
When you begin to explore the world of sharpening, one question quickly arises: What does "sharp" really mean to you? For most people, a sharp knife simply means one that can slice through a tomato effortlessly. But for trained sushi chefs, a truly sharp knife means the ability to slice through the individual cells of ingredients without crushing or tearing them. The definition of sharp depends heavily on your needs and context, so ultimately, it’s about what matters to you. Trust your own judgment—there are few "wrong" answers. That said, if your knife struggles to cut through paper or a tomato, it’s almost certainly time to sharpen it.