Rice husk ash (RHA) as a silica source was studied, resulting from burning at a temperature of 700oC in an electric furnace. RHA consists of inorganic, incombustible matter in the rice husk that has been fused into an amorphous structure. Microscopic techniques, such as X-ray fluorescence (XRF), X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to observe the surface and internal structure of the RHA. The results among other things revealed that RHA consist of mainly SiO2, with amorphous structure, Microscopic examination showed that has a porous cellular structure and consists of irregular-shaped particles.