| Lustre is how well the light reflects
from the pearl back to the eye. When looking at a
cultured pearl, a window/box reflection is noticed. The
sharper and more intense this reflection is, the higher
the lustre. 
- Very high lustre: The
reflection is so brilliant the box appears to be
like a mirror. This level is very rare and hard
to obtain
- High lustre: The
reflection is very strong, the appearance is like
a ball bearing, the box reflection is still sharp
and clear
- Medium lustre: The
reflection is slightly fuzzy, the pearl still
appears to be solid
- Low lustre: The
reflection is fuzzy, the pearl appears to be flat
and possibly chalky in appearance
- Very low lustre: The
reflection is almost non-existent, very fuzzy,
difficult to discern the box. Appearance very
flat and very dull
| Lustre |
Grade |
| Very high |
10 |
| High |
8-9 |
| Medium |
5-7 |
| Low |
3-4 |
| Very low |
1-2 |
|
|
