Collecting Diamonds - A proposed New Problem

Yeah and it seems so :) It throws a number of observations at once, but none of them provide immediate clue!

Thank you very much, it is ready:

Collecting Diamonds

As a sidenote this King looks quite greedy, reminding of the tale of the Roman general Terentius who was proposed reward by emperor - in form of the sequence of coins doubling in size. I can't find the source - here it is pretty well known from Jacob Perelman's 1934 book "Live Math" for kids - and I only found a comment that "the tale is and adaptation from the story found in manuscript in one of private collections in England".

Clive:

This is awesome; thank you.

Very much a problem in your style: eminently fair, with all the clues right in the text, yet with enough landmines to make the solvers trip on their first try.

V.