Mystery pearl pendant that belonged to my mother

Well, look at what this ride "down the rabbit hole" has brought you :D
Once you fill in the gaps you will have quite a story for your pearl!
Thank you, Douglas and parfaitelumiere! I’m still in a state of astonishment. My best guess is still that it came from the Middle East, from the Arabian Gulf. The friend’s son worked in Kuwait for several years in the 1970s, and I know he gave his mom a lot of nice and thoughtful gifts. Of the natural pearls I’ve seen online, this one most resembles Pinctada radiata. But I’m no expert, and my judgment is subject to the quality of the photos.

Also, Mother’s pearl strikes me as being relatively large/heavy. Even with the hole, it weighs .8 gram/4 carats.

I will be sleuthing some more. I remain super grateful for your time, advice, and interest!

this looks like real pearl.
I mean, natural one, I also saw the unmounted pictures, for me it's natural pearl even on mounted pictures.
So, you see...the "gaps" are slowly being will end up with a "living story" in that little pearl. Should end up closer to your heart :)
A question for Douglas,I’m a bit puzzled,in an earlier comment you said this gorgeous Pearl could be natural or freshwater.Aren’t early river pearls
Naturals too? Are they less rare or valuable than natural saltwater pearls?
Yes, indeed barbaradilek and when I said Natural, I did encompass both salt & fresh-water pearls.
I don't have that much knowledge on the present situation of freshwater pearl fisheries, but I believe -and it's just my very personal opinion- that river pearls are much rarer TODAY than saltwater pearls.
Because most freshwater pearly mussel species are under strict fishing policies, and pearl oysters are not (there are places where they are very well protected, such as Australia) that protected, especially in Latin America where huge fisheries have been the norm for the last decade. Mind you...the fisheries are for the MEAT, but the pearls are a by-product and not the target of the fishery. Anyway, these huge fisheries have led to large amount of "new pearls".

Now, regarding value or pricing...I believe the market presently is under a flux and is unstable (according to what I have been told by some friends in that industry), so pricing is also under this spell. I don't really know if natural river pearls should be more valuable than saltwater ones because of this, but they have always been less valuable (historically speaking) ...perhaps they should be equally valuable! But the Natural Pearl Market is quite unique, and I don't really know how it is "moving" since 2020.