The largest known pearl in the world, Pearl of Allah, was found in Philippines in 1934. It is a natural, non-nacreous, calcareous concretion pearl from a giant clam. It did not grow in a pearl oyster and hence it is not pearl-shaped, but instead, it has a porcelain-like surface, or glossy like a china plate. Other pearls from giant clams also exist, but this is a very large one.
This pearl is the product of a giant clam, Tridacna gigas, which cannot be grafted. The pearl is also a whole pearl, not a mabe pearl, and whole pearl culturing technology is only 100 years old.
Pearl of Allah is not a gem-quality pearl, but a rare very costly natural pearl. It measures 24 centimeters in diameter (9.45 inches) and weighs 6.4 kilograms (14.1 lb). It is an interesting piece of natural history surrounded by extraordinary stories and legends.
It was discovered by an anonymous Filipino Muslim diver, off the island of Palawan in 1934. According to legends, a Palawan chieftain gave the pearl to Wilbur Dowell Cobb, an American, in 1936 as a gift for saving the life of his son, who was stricken with malaria. The pearl was named the ‘Pearl of Allah’ by the Muslim tribal chief, as it resembled a turbaned head.
After Cobb took the pearl to USA, it was exhibited at the ‘Ripley's Believe It or Not! Odditorium’ in New York, and it was valued at $3.5 million. Gemologist Michael Steenrod in Colorado Springs has appraised the pearl at $60 million in 1982 and $93 million in 2007. Another 1982 appraisal, by Lee Sparrow of the San Francisco Gem Lab, value the pearl at $42 million.