Hi Janet,
I'll be following your thread with interest because the term hanadama has cropped up in answers to my posting (Consumer Pearls Q & A: Deciding on a new necklace) and I'm sure you will get a lot of answers from the specialist members.
I saw some information about hanadama grade pearls on
www.hanadama.com as well as on
www.americanpearl.com and I know that Pearl Paradise and several other companies whose representatives contribute regularly to the Pearl-Guide forums sell hanadama necklaces - at least occasionally.
The hanadama certification seems to be a guarantee of top quality equal to Mikimoto AAA and considerably higher than most other AAA graded Akoyas.