The world's first Tridacna Gigantea pearl found?

by Volker Bassen
(Diani beach, Kenya)

The world's biggest Tridacna Gigantea clam (612kg!)

The world's biggest Tridacna Gigantea clam (612kg!)

I came to Kenya in 1990 and started collecting fossil Tridacna Gigantea (giant clams) in 1995.

Tridacna Gigantea is a diffrent clam compared to Tridacna Gigas. First of all; Tridacna Gigantea doesn't exist live in the wild because they became extinct around 180.000 years ago as sea levels suddenly rised about 20 meters (God doesn't make them anymore) so suddenly they didn't get enough sunlight (which they need as they live in symbiosis with an algae that produces sugar for the clam to feed on) so they basically starved to death. Secondly, they became much bigger than today's Tridacna Gigas, the biggest one in my collection has a staggering weight of 612 kg! (See photo) I also have a single clamshell which weighs 211kg cleaned and polished. The biggest Tridacna Gigas ever found only weighs about half that. Thirdly; they are much rarer than Gigas clams as they are only occasionally found, very deeply embedded in ancient limestone quarries, about 4-5 meters deep (the deeper, the bigger the clam, see photo)
Over the years I collected quite a few, my dream was to one day find a pearl in one of them.
I set up a workshop in Kenya where I live and we started polishing and selling these amazing clams through different outlets such as Bonhams and other high-end outlets. In Europe and the US they are often used as luxury washbasins (see photo) Yesterday my dream came through as we finally found a pearl stuck to the wall of a "monster" clam, one of the biggest I've ever recieved during my 20 years of collecting these giants.
As far as I know it's the only Tridacna Gigantea pearl ever found. I actually found 2 as they apparently grew next to each other! (See photo) I know that some of the pearls found in Gigas clams are hollow but not these ones, they are quite heavy. So now the big question; does anyone know of any other pearl ever found in one of these Gigantea clams?

Warm regards,


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Apr 08, 2021
T. Gigas vs T.Gigantea
by: Anonymous

The main difference between Tridacna Gigas and Tridacna Gigantea is that T.Gigantea became extinct during the later Pleistocene period around 180.000 years ago. They don’t exist anymore whereas T.Gigas can still be found alive around the South China Sea. Another difference is the size. The largest ever T.Gigas was found in Okinawa 1956, weighing 270Kg. The largest in my collection is a staggering 530Kg, almost twice the size!

Jun 27, 2020
My shell
by: Laurel

Could you tell me any differences between the gigus and gigantea clams apart from their size
Also.. I have my shell, (which I salvaged from a derelict hose 😳) in the garden as a bird bath. It’s lovely to see them bathe in it.
How can I protect and maintain it? Should I bring it indoors in the winter ie. is frost bad for it?

Jun 20, 2019
Gigantea pearl
by: Anonymous

I have tridacna gigantea pearl. It is different from the tridacna gigas pearl. My grandmother told me before that pearl was from the extinct tridacna gigantea

Oct 19, 2018
Giant Tridacna Gigas
by: Anonymous

Hi Mr. Volker, Greetings from Philippines Neg.Or.
I will send you a picture of Tridacna gigas. 13 of them from
151 kilos, 133, and 150 kilos and the rest is less than 100 kilos. I am glad that I stumble your site. This was buried for 400 years and was found in the hill side of the mountain,owned by my relatives property here in Negros Oriental, Philippines not in the seashore.Thank you for this opportunity, I really appreciate this moment. Thank you very much. Sincerely, Susan J. T.

Aug 05, 2015
Gigantea Pearls
by: Kari

I would say if anyone could claim the first Tridacna Gigantea pearl found that it would be you. These shells are totally amazing not just for their size but for the location they are found in and for the fact that they are extinct and not encumbered by CITIES regulations.

The two fossil pearls are fascinating. I'd love to see them after being cleaned up if you decide to do that. I hope you find more.

Congratulations on being the first to find these rare and extinct pearls!

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