The largest one of these came from a giant clam in the Philippines and weighed about 14 pounds. What was it?

The enormous object described, weighing approximately 14 pounds and originating from a giant clam in the Philippines, is indeed a natural pearl. These fascinating formations occur when an irritant, such as a parasite (Review) or a grain of sand, enters a mollusk. As a defense mechanism, the mollusk secretes layers of nacre, or in the case of giant clams, a different calcium carbonate material, around the irritant. Over many years, these layers build up, eventually creating the lustrous or porcelain-like gem we know.

While most commercially valuable pearls come from smaller bivalves like oysters, the colossal Tridacna gigas, or giant clam, is known for producing the largest non-nacreous pearls. These "clam pearls" often lack the iridescent shimmer of traditional pearls, instead possessing a smooth, porcelain-like texture. The sheer scale of a 14-pound specimen makes it an extraordinary natural wonder, showcasing the incredible biology of these massive marine creatures that can live for over a century.

This particular find likely refers to the "Pearl of Allah," also known as the "Pearl of Lao Tzu," discovered off Palawan, Philippines, in 1934. Weighing 14 pounds and measuring nearly ten inches in diameter, it holds the record as the largest known non-nacreous pearl. Its immense size makes it a unique geological marvel rather than a traditional jewelry gem, offering a rare glimpse into the astonishing natural processes occurring deep within the ocean.