The largest pearl in the world is not a gemstone, but a clam pearl. Because it grew attached to the shell of the giant clam, the Pearl of Lao Tzu, previously known as the Pearl of Allah (REPRODUCTION ABOVE), is called a blister pearl and it weighs in at an incredible 14.1 lbs (6.4 kg). It is as big as a man's head, specifically – in the eyes of a Muslim tribal chief in the Philippines, where it supposedly originated – the turbaned head of the Prophet Mohammed, hence its name. The [first] story promoted by American Wilburn Cobb, who came into possession of the giant pearl in 1939, is what intrigued me when I read about it yesterday. I was talking with someone* about the longevity of certain animals, and I mentioned clams, so we consulted this article and learned the legend. Supposedly, a Filipino diver had come across the clam off the island of Palawan. He had been diving for conchs and accidentally or deliberately reached into the giant shell, which slammed shut on his arm with the force of a bear trap. It never released him and he drowned. It took it his fellow divers 4 days to find and recover his body. When they brought it up, they also retrieved the clam that contained the Pearl of Allah, the history and ownership of which is in dispute.