We have developed a novel 3D polymer template composed of a self-assembled film (SAF, insoluble polylactide film) and a soluble modifier (poly allylamine) and used this template to synthesize barium carbonate with a complex superstructure. Controlled synthesis of barium carbonate with novel morphologies such as spherical crystals consisting of needle-like building blocks. flower-like congeries consisting of one pronounced backbone and many shuttle-like petals, raft-like barium carbonate bundles consisting of tiny fractions etc., was realized by finely tuning the alignment and self-assembly of rods using the double template. The observed crystallization can proceed along the so-called rod-dumbbell-sphere formation process. This approach will be further extended to polymer-controlled fabrication of related minerals with novel, complex superstructures. (C) 2009 Elsevier Ltd. All rights reserved.