After treatment with 3 N HCl the appearance of TRH1 [Fig. 1(b)] is not much different from that of RRH [Fig. 1(a)]. The silica is present all over the rice husk but is concentrated in protuberances and hairs (trichomes) on the outer epidermis, and also in the inner epidermis (adjacent to the rice kernel).11 The remaining areas lean in silica or rich in organic matter were attacked. Slight smoothening around the protuberances and trichomes, and widening of parallel grooves between the protuberances can be seen. But after treatment with 5.6 N HCl the THR2 appeared like charred RHs with a fragile nature [Fig. 1(c)]. From smoothing of the surfaces and relative shrinking, the areas leached out due to chemical burning can be seen. The extent of attack of HCl acid on organic matter in RH can be seen in Fig. 1(c). The protuberances and trichomes (horns) rich in silica11 are not affected.