DeBeers NY Times add

[Chelsea Palmer]

I am sure the markups are higher on bigger stones because they always cost 4 times more for double the carat weight in natural diamonds.
So even though smaller stones cost less per carat at wholesale, what retailers can get away with has a more profound impact.

Thank you Garry. After reading your response, I think I misread the first post that had me questioning why one carats cost more than bigger carats.

 

[Texas Leaguer]

It's incredible how little it costs to make / polish Chinese HPHT LGD's....
They actually had to instigate a min floor for rough...No wonder they can sell a 1ct polished for under $50

It takes the Earth more than a billion years to forge a diamond. Feng Canjun can grow one in the space of a week.

The prices have got so low in China that the government has intervened. In Henan, the provincial government is behind the formation of a new diamond association — a move that echoes a broader crackdown on destructive price wars in sectors such as electric vehicles. One of the association’s first moves in March was to set a minimum price of $15 per carat for rough diamonds weighing between one and 10 carats.

Once roughly processed, the stones are shipped to Surat, India — the world’s diamond polishing capital — where labour costs are lower. Feng estimates it costs Rmb400 ($56) to polish one carat in China, more than it costs him to produce the stone, compared with just Rmb86 in India. *86RMB = $11.98

https://archive.is/k9JD2#selection-2445.0-2445.281

It's ironic, especially at this particular time in our politics, that diamonds produced in Chinese factories have become the "socially responsible" product in the minds of so many American consumers.