[DocTomoe]

Call me naive, but wouldn't this be a lot easier - and more low-tech, thus cheaper, to sort by size with a sieve, then weight individual size-bags, and divide by the size of one pearl?

Assuming all pearls have comparative density.

[viraptor]

So you need to make / order sieves, then get the counting person to sort, bag, weigh the items, calculate results. This will have a lot of mistakes too. And you end up with a process working only with that type of pearls. (Edit: forgot the solution debugging time)

The alternative here is to point the phone at a table.

The labour costs are relatively high and dominate most business costs. $100/mth is a rounding error in comparison. If you saved 4h of median-us-wage of work a month, it's free.