How long would it have taken for the “Palawan Princess” to develop inside the giant clam ?
If the growth rates of giant clam pearls are known we can make an estimate as to how long it would have taken for the pearl to develop inside the clam. But, unfortunately, growth rates of giant clam pearls are not known, even though the growth rate of the giant clams themselves in captivity are well known. The growth rate of giant clams has been estimated at 2 inches (5 cm) per year in young individuals. Growth rate slows down in older clams. Their life span is quite long but uncertain. Estimates of the life span vary from 50 to 100 years. The rate of deposition of nacre in oysters and mussels, producing nacreous pearls is very slow, and in most species it’s about 0.6 mm per year. If we apply this rate to the “Palawan Princess” having a diameter of 6 ins (15.2 cm); assuming that the pearl is spherical and the growth is even right round the pearl, centered around a point in the middle; the time taken for 7.6 cm of nacre to be deposited at the rate of 0.3 mm would be 76/0.3 = 253 years.