We investigate the sodium inward diffusion (i.e., sodium diffusion from surface toward interior) in iron containing alkaline-earth silicate glasses under reducing conditions around T-g and the induced surface crystallization. The surface crystallization is caused by formation of a silicate-gel layer first and then the growth of silica crystals on the glass surface. The type of alkaline-earth cations has a strong impact on both the glass transition and the surface crystallization. In the Mg-containing glass, a quartz layer forms on the glass surface. This could be attributed to the fact that Mg2+ ions have stronger bonds to oxygen and lower coordination number (4-5) than Ca2+, Sr2+, and Ba2+ ions. In contrast, a cristobalite layer forms in Ca-, Sr-, and Ba-containing glasses.