We have fabricated magnetic granular Fe‐SiO2solids over a wide metal volume fraction range 15%–100%. The microstructure of the samples has been characterized by using transmission electron spectroscopy, electron diffraction, and Mo¨ssbauer spectroscopy. Giant magnetic coercivity, as high as 2500 Oe, has been observed in samples with nanometer particle size. The behaviors of coercivity across the metal volume fraction range are attributed to the change of particle size and percolation effect.