You could imagine very easily that if there’s a 20% price jump from a 0.99ct diamond to a 1.00ct diamond, the cutter who loses that 0.01ct trying to make a prettier stone will lose his job.
Perhaps with the nicer cut it will only be worth 15% less instead of 20%, but either way, it’s a big loss. This kind of price manipulation by maintaining weight categories has been taken to an extreme by many of the world’s largest diamond companies.
They will take rough diamonds with diameters that really should have only been used to make a 0.75ct-0.85ct diamond (with the proper cut to maximize brilliance), but instead will keep them over 0.96ct to sell them as 1ct diamonds to the major jewelry chains like Kay or Zales.
Even though they will have to sell these diamonds at steep discounts compared to well cut 1ct diamonds, they are still sold at a significant premium to well made 3/4ct diamonds.
The lesson here is, like above, not to get too attached to a diamond that’s within a certain carat weight category. A well cut 0.9 carat diamond will look significantly more beautiful than a poorly cut 1.00 carat diamond, all while costing either the same amount or slightly less.
Например, look at this 1 carat, H color, VS1 diamond. It has a relatively low cut grade (Добре), and it clearly shows when you look at the diamond. Meanwhile, this ever-so-slightly smaller 0.90 carat diamond has a far better cut quality and looks more attractive at a similar price.
We’ve covered this topic in more detail in our guide to diamond cut quality. Cut is possibly the most important of the 4 Cs, making it something you’ll want to understand before you shop for any type of diamond.