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.
They could use a simple sorting machine that sorts pearls based on size (like how most coin sorting machines work - run all coins over a small hole, the smallest coins fall through, then run have a slightly larger hole after that, and so on).
Then they could have a simple optical/laser sensor below each hole to count how many smallest, smaller, small, medium, large, larger, and largest pearls fall through each hole.
The benefit would then be that if customers wanted pearls of a certain size, they are already sorted.
Maybe there is an enterprising user here that reads this, can easily create it, and reaches out to pearl companies.
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.