The best lustre is considered to be “bright” with the ability to see an object’s reflection on the surface. The luster exhibited here is less than ideal, the reflection is dull and out of focus.
Surface cleanliness refers to bumps, cracks, or spots on the surface of the pearl. Of course, the cleaner the surface the more valuable the pearl. This pearl has several pits and some ripples in the surface.
Color is really a matter of personal preference, though rose or silver/white usually look best on fairer skin types and cream or gold pearls look best on darker complexions.
Pearls are formed in nature, so a perfectly round pearl is rare. The rounder the pearl, the more valuable it is. The sample shown here is out of round and “lumpy” and may be a sign the oysters were not properly tended during the culturing process. Also common are pearls that appear round but when rolled can be seen to wobble. Baroque is the name given to off-round pearls whose shape is very organic and natural.