Blasting abrasive at high pressure for an even grey finish. Low reflection & glare but prone to rust especially in humid conditions.
Usually done by hand and attractive. Has better corrosion resistance but needs frequent polishing. Scratches easily.
Reduced reflection & glare, corrosion & wear. Coating may come off entirely over time. Quality coatings are mostly bonded electrically, thermally or chemically.
One of the more common finishes, it is less shiny than mirror polished but still has relatively decent corrosion resistance.
Tumbling the blade in an abrasive material & usually has darkened appearance. High rust resistance & little maintenance, hides scratches & fingerprints easily.