Which naturally occurring material forms a permanent magnet?

The correct answer is Option (3) → Lodestone

Materials that keep their magnetisation after the external field is removed are hard ferromagnets, and they form permanent magnets. Alnico is one of them, but it is an alloy of iron, aluminium, nickel, cobalt and copper. The one that occurs in nature is lodestone.

NCERT (2026-27):
Ferromagnetism – “… In some ferromagnetic materials the magnetisation persists. Such materials are called hard magnetic materials or hard ferromagnets. Alnico, an alloy of iron, aluminium, nickel, cobalt and copper, is one such material. The naturally occurring lodestone is another. Such materials form permanent magnets to be used among other things as a compass needle.”