What is the difference between black iron and galvanized iron pipe?

Black iron pipe is made from carbon steel and has a dark, oxidized finish. It is primarily used for gas lines and is not suitable for carrying water due to corrosion. In contrast, galvanized iron pipe is coated with a layer of zinc to prevent rust and corrosion, making it suitable for water supply and Plumbing applications. The zinc coating gives it a shiny appearance, while black iron pipe is more commonly used in applications where corrosion resistance is not a priority.