Why is magnetite considered the most magnetic common mineral?

Magnetite (${\text{Fe}}_3{\text{O}}_4$) is considered the most magnetic common mineral because it exhibits a strong form of permanent magnetism known as ferrimagnetism.12

This property arises from the specific arrangement of iron ions within its crystal structure. Magnetite contains both iron(II) (${\text{Fe}}^{2+}$) and iron(III) (${\text{Fe}}^{3+}$) ions. While the magnetic moments of the iron(III) ions are paired in opposite directions—effectively canceling each other out—the iron(II) ions align in the same direction. This alignment creates a net external magnetic field, which is responsible for the mineral's notable magnetic strength.1

Because of this structure, magnetite is the most magnetic of the common rock-forming iron oxide minerals. While other ferrites also exhibit ferrimagnetism, magnetite's specific composition and crystalline configuration allow it to maintain a significantly higher magnetic susceptibility compared to other common minerals, such as hematite.3