Étude des défauts créés lors de perturbations extérieures imposées au cours de la croissance hydrothermale de calcite

In order to elucidate how defects appear during growth, known perturbations have been generated and the nature of the defects they induced was investigated by means of X-ray topograohy. They are essentially growth bands, inclusions and dislocations. The growth rates could be determined and it was shown that the presence of dislocations increased the growth rate inasmuch as they have a strong screw component. Furthermore, nearly dislocation free and perfect crystal has been observed on “S” type faces, according to Hartman's classification.