I have several necklaces from art deco or early period, with akoya pearls, most of the times pearls are yellowish, quite irregular, but not so bad, the main issue is often an banded color inside, if the pearls have been worn a bit, the color can be seen through.
I think I probably found several strands from the 20's, I am in France, maybe it helps.
However there is something I don't understand.
The brand "Tecla" is selling cultured pearls for a long time now.
Sadly it's not very easy to understand, as cultured pearls had a bad reputation in the early period, maybe they used the term "man made, artificial , scientific" to describe cultured pearls?
And based from this add from 1926, they do it for 25 years, making the brand born in 1901.
However as they are describing a "new process", is the new process a cultured pearl from Japan, and older process a simulated glass bead pearl?
I have another add, from 1937, talking about pearls "directly from orient", and before the 30's, nothing specifically mentionning cultured pearls, only "scientific" "imitation" or "professor tecla" pearls.
What is weird is when you phone to the brand (still existing) they don't even know the company already existed at least since 1908 (oldeds adds I found) and moved from 10 to 2, rue de la paix, in the 30's