It's what is known as a "stonewashed" or "tumbled" finish. The blades are put into a bin with hard media, not sure what Benchmade uses, that's proprietary information, but think of it as pebbles, if you will, and then the whole thing, blades and media are tumbled around for a while. This is similar to how they polish stones for jewelry, but there the difference in hardness between the stone and the media is higher so it actually wears away at the stones. The resulting finish is somewhat mottled in appearance. It is subtle and doesn't photograph well, at least with the digital camera I have. Benchmade tried a number of media types before we found the right one that created the appearance I wanted, a bit more apparent than they have done before.

It is a subdued finish, but not as dull as a beadblasted finish, but much more attractive, in my opinion. It has a certain "luster" to it, especially in the right light. Unlike beadblasting, which tends to open the pores of the metal, stonewashing tends to seal it up, more like a polishing, so it adds a layer of protection. It will scratch, just as will any natural finish on a steel blade, but it is fairly resistant to wear.

Hope this answers your question.