[smetzler]

Originally Posted by Bodecia

Love to hear more this time around.

The Cook Islands/Manihiki pearl harvest is not that large, although it does rank second only to tourism in importance to the local economy.This is a start, giving a rough timeline (update: Penryhn lagoon has been almost totally abandoned, leaving Manihiki with the monopoly).
Pearl World featured the Cook Islands last year (backissues are likely available), with yours truly as featured 'pearl nut', editor Bo Torrey having a soft spot in his heart since a visit there in the mid-90s. As the oyster, P. margaritifera, is the same as in Tahiti, any differences result from water conditions and farming techniques. The range of sizes and colors (and prices) is comparable to Tahiti, CI with a greater tendency towards green in its exotics.

Chinese and Japanese merchants purchasing the bulk of the harvest are certainly known to offer Cook Islands pearls to the world as Tahitian. There are plenty of challenges ahead—let's hope this thread attracts some local input for the best information.