Jersey Pearl, that is certainly a fair question. At least 95% of what I know about pearls was learned right here on the forum over the past 10 years~supplemented with visits to gem shows and examining pearls of many qualities.
With the introduction of bead nucleated freshwater pearls from China, identification has gotten more challenging, for sure, and is more difficult from photos than in person.
So let's take a look at some of Mary's Timeless Treasures,
Tahitian Pearls
So these are some of the red flags on
Mary's Timeless Treasures listings:
1. Is the price too good to be true?
2. Are the pearls color treated? The blue/purple/aqua/copper is characteristic of dyed freshwater pearls. Color treated chocolate Tahitians are fairly new. High quality are not inexpensive~check out the beauties at PP! This is not the kind of color matching done with Tahitians.
3. Are the pearls bead nucleated? Even in a baroque pearl the bead can be apparent. If the pearls are slightly flattened to clearly oval and elongated, they likely are tissue nucleated freshwater. Mary has 3 strands of "Tahitians" (actually freshwater pearls) with sales pending all 3 dyed and of a size and shape that wasn't available until well after 1990, the year she gives as when these pearls were stored away. And note the copper strand of "Tahitians" at the bottom of the page, sigh. I haven't taken time to check out the other listings described as Tahitians , but until I do all are suspect.
4. Are the quality (& blemishes) and size typical of the type of pearl being offered for the asking price?
5. Consider the seller~are they someone known to be knowledgeable about pearls? Does the story they are telling add up? Mary MAY know vintage akoya pearls, but she is certainly misrepresenting Kasumi and Tahitian pearls.
Apologies for being away from home and working on a slow computer. Please, pearl friends, do add to this list as you see fit.