Composites of calcium silicate and carbon nanotubes have been generated. The nanotubes are multi-walled and grow on catalytic hematite particles, which have been deposited on the calcium silicate carrier previously. Randomly curled as well as straight nanotubes have been observed. The nano-structured calcium silicate crystallizes at the elevated temperature and reaction conditions used in the formation of the carbon nanotubes. The silicate forms wollastonite, therefore reducing the high surface area of the amorphous material. Various carbon sources have been explored, which allow catalysis at lower temperatures. (C) 2003 Elsevier B.V. All rights reserved.