Why is magnetite considered a strongly magnetic common mineral?

Magnetite (${\text{Fe}}_3{\text{O}}_4$) is considered a strongly magnetic mineral because it exhibits a property known as ferrimagnetism.12

Unlike purely ferromagnetic materials, where all atomic magnetic dipoles align in the same direction, ferrimagnetic materials like magnetite contain multiple sublattices of atoms with magnetic moments that align in opposite directions (antiparallel). In magnetite, the iron ions are present in two states: ${\text{Fe}}^{2+}$ and ${\text{Fe}}^{3+}$. While the ${\text{Fe}}^{3+}$ ions are paired off in opposite directions—effectively canceling each other out—the ${\text{Fe}}^{2+}$ ions align in the same direction. This unequal distribution results in a net spontaneous magnetization, which accounts for the mineral's external magnetic field.12

Because of this structure, magnetite is classified as a ferrite, a class of materials that possess properties such as remanence and spontaneous magnetization. This natural magnetism has been recognized since ancient times, when the mineral was known as lodestone.132