Fe(III)-silicate precipitation tubes synthesized through "silica garden" route have been characterized using a number of analytical techniques including X-ray diffraction, infrared spectroscopy, atomic force microscopy, scanning and transmission electron microscopy. These tubes are brittle and amorphous and are hierarchically built from smaller tubes of 5-10 nm diameters. They remain amorphous at least up to 650 degrees C. Crystobalite and hematite are the major phases present in Fe(III)-silicate tubes heated at 850 degrees C. Morphology and chemical compositions at the external and internal walls of these tubes are remarkably different. These tubes are porous with high BET surface area of 291.2 m(2)/g. Fe(III)-silicate tubes contain significant amount of physically and chemically bound moisture. They show promise as an adsorbent for Zn(II), and Cr(III) in aqueous medium. (C) 2010 Elsevier Ltd. All rights reserved.