That is a good point Lee.
The luster or fire never fades but rather, it may never have been there.
Nacre is the crystalline layer that creates the luster. That nacre layer depends on everything in the animals life from habitat to food sources to temperature to PH of the water it lives in.
You MOP lovers will love the information about the creation of your handles.
https://www.gemselect.com/gem-info/moth ... -pearl.php
That is just one site with a basic overview. You could actually take a semester in school, and still just learn enough to know what questions to ask.
My sister has her doctorate in Sustainable marine bio-science. (fancy title for a girl that saves sharks, and turtles but tries to run over hitch hikers) She wrote the papers on the decimated clam beds out in the Hamptons/South Fork, Long Island. Clam is a source of MOP. Not high grade like Abalone or Ormer but related
Point is MOP is graded just like any other gem stone BUT it is formed by the secretions of a living animal, and its environment. The variations are almost infinite.
Ken Mc.
WTB Kershaw 2120 MACHO Lockback Parts knife
I need a pile side scale. THX!