Two assessment methods are essentially used
The luster of a pearl is made up of luster and orient. The luster or shine can be assessed by the more or less perfect reflection of light on the surface of the pearl. A very beautiful luster corresponds to a total reflection of light giving a mirror effect. On the contrary, the lower the gloss, the duller the effect.
As for the Orient, it defines the iridescence of the pearl which results from the decomposition of light through pearly secretions. A beautiful orient then results in a soft rainbow hue, similar to that which colors the soap bubbles.
Estimate the value of a pearl
Generally the larger the diameter of the pearl and the more its shape is round, the higher its value. However, this rule does not always apply, the value of a large pearl of poor quality may indeed prove to be less important than that of a smaller pearl without surface defect. However, the very specific color and luster criteria for the cultured pearl of Tahiti will be the most determining for connoisseurs.