The relation between crystal morphology and crystal structure and binding has been a field of impressive development thanks to the work of Hartman, Perdok and Bennema. However, crystal morphology and habit can be also greatly influenced by crystal growth environment. This work is focussing on this aspect. Silver halide crystal growth is good example of this influence and a subject of high industrial interest. A study of the effect of the solvent on the relative stability of crystal faces lead us to the discovery of a new method for the preparation of silver halide crystals with a desired crystal shape. This method is based on the use of polar aprotic solvents and it has the advantage of very high silver halide solubility. This method allowed the observation "in situ" of silver bromide crystal growth and the investigation of tabular and rod crystal morphology and twin plane structure. It is observed that crystal growth is related to roughness on crystal sides determined by the presence of twin planes. Previous mechanisms of silver halide crystal nucleation and growth are discussed in the light of new experimental evidences and new mechanisms are pointed out.