This is Not a Pearl

This is not a pearl.

giant clam pearl 1.jpg

The giant clam, Tridacna gigas, is under attack. The rumor mill never rests on the subject of giant clam “pearls”. They are supposed to be worth millions, if not hundreds of thousands of dollars.

Clam pearls, technically calcareous concretions, do exist. Good clam pearls most often come from Tridacna squamosa, the giant fluted clam, although they can be found in Tridacna gigas. The Tridacna squamosa is much smaller than Tridacna gigas, whose enormous shells have been used as baptismal fonts.

The best of these pearls have a gelatinous appearance that sparks to life when a pinpoint light source is directed at the surface. A flame pattern reflects from within as seen in the photo below.

Blaire Beavers Tridacna Pearl.jpg

Having seen a real clam pearl that grew free within the flesh of the animal, and not attached to the shell, it’s hard to reconcile this beautiful image with the steady stream of images received from promoters of “clam pearls”.

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When a pearl is attached to the shell, it can be considered a blister pearl, up to a point. When it merges with the shell and grows with banded patterns, it is considered part of the shell and not any kind of pearl. In the same way that mineral crystals may have more value if they are attached to the matrix they grew in, these growths can have value if they are left in their natural state, attached to the shell, and not polished or cut.

In parts of the world where marine resources are rich, but life may be difficult, it can be hard to resist the siren call of the search for treasure. The blame for this lure lies with the first giant clam pearl to be publicized, the “Pearl of Allah”. As the specimen passed from promoter to promoter, they created competing legends of how it was created or found. And they fabricated higher and higher values and dubious appraisals to support their claims.

The result has been a lot of disappointed treasure hunters and a lot of dead clams. And yet, the rumor is evergreen. It will not die, no matter what is published.

Although it may not have the desired effect, I’d like to make one more attempt here at
For those seeking to sell giant clam pearls – just stop.
All of us here, and all people involved with pearls are tired of your messages, emails and calls.

What you have found may have little monetary value. Especially if you have cut it from the shell, and even more if you have worked it by sanding and polishing. These are not gems. A gem has three characteristics: beauty, durability and rarity. What you have is not beautiful, and now, is no longer rare.

Our community carefully followed the story and two of our members, Caitlin Williams and Kathie Hodson researched and wrote an article on Pearl Guide, The Pearl of Allah: The Facts, the Fiction, and the Fraud here. The thread that prompted them to do this can be followed here.

Update: A Filipino TV show about a man who found giant clams while excavating a pool at his resort, showed competing views by a marine biologist and educators of whether they were pearls or shell. In gemological terms, these are not pearls.

A laboratory is also saying that these growths are pearls and that a chemistry report can prove it. Pearls and shell are made of the same material, therefore a chemistry report is meaningless. These items have no value. Ask yourself, "How much would I pay for a piece of shell?" and you will have your answer.

Blaire Beavers
Managing Editor
Pearl Guide News