The picture in the bottom of the article shows that varying sizes of pearls need to be counted at the same time, making using weight very unreliable.
Even if only similar size pearls are allowed, small variations multiplied by a large amount of pearls can cause issues, such as distinguishing 100 pearls of 99 grams each from 99 pearls of 100 grams each.
Even if only similar size pearls are allowed, small variations multiplied by a large amount of pearls can cause issues, such as distinguishing 100 pearls of 99 grams each from 99 pearls of 100 grams each.