The effect of sequentially doping a supersaturated solution of copper (II) acetate monohydrate with propan-1-ol has been determined from a study of the crystal habit during growth. Crystals grown from 100vol% propan-1-ol yielded needle-like crystals, which were physically elongated parallel to the b-axis. In contrast, those grown from aqueous media were orthodome with the {101}, {011} and {110} faces dominating the morphology. Crystals harvested from water/propan-1-ol solvent mixtures evidenced two related growth forms whose morphology can be rationalised in terms of the crystal/solvent interactions during their formation. This study highlights the impact of solvent identity on the crystal morphology and draws renewed attention to the importance of solvent purity in crystal growth assays. (C) 2002 Published by Elsevier Science B.V.