In this paper a methodology for an automatized measurement of the nacre thickness of Tahitian pearls is presented. An adapted snake approach as well as our own developed circle detection algorithm are implemented to extract the nacre boundaries out of X-ray images. The results are validated by experts currently performing manually the obligatory nacre thickness control for millions of Tahitian pearls that are exported each year. Equivalent articles propose methods suitable for round pearls, whereas this paper contains methods to evaluate the nacre profile of pearls independently of their shape. As the algorithms are not specifically parametrized for Tahitian pearls, the methods can be adapted for quality assessment of other pearls as well.