The rarity of the Case Hardened Skin varies from weapon to weapon. The Karambit is the rarest of the knives with this skin, and is usually the most expensive. The Butterfly Knife is the second rarest, followed by the Bayonet and M9 Bayonet. The rarity of the Case Hardened Skin is determined by the pattern of the blue and yellow on the knife. The rarest patterns will have a lot of blue, while the more common patterns will have a lot of yellow.
Overall, the Case Hardened Skin is one of the most popular and sought after skins in CS2. It is available on all weapon types, but is most commonly seen on knives. Explore related collections: Blue Steel, Damascus Steel and Gold.