D2 is a high-carbon, high-chromium tool steel that has been a workhorse in the knife world for decades, particularly in production folders and fixed blades where wear resistance is prioritized. Its high chromium content pushes it into semi-stainless territory — it resists rust better than plain carbon steels, though it's not immune and benefits from occasional maintenance. The payoff is exceptional edge retention: D2 will outlast most conventional stainless options on the cutting board and in the field. It sharpens best on diamond or CBN abrasives and develops a distinctive, slightly toothy edge that many users prefer for cutting tasks.