A broken diamond is not a broken diamond. A broken diamond is also a complete diamond, and it also has a complete cutting surface. The quality is the same as that of big diamonds. See 4C standard. Only the weight is less than 10, and those below 10 are broken diamonds, and those above 10 are not broken diamonds.
Broken diamonds are also sparrows' small diamonds. A complete diamond has broken diamonds in every part. The value of broken diamonds is not expensive, but it is relative. A single small broken diamond can't fetch a good price. However, when assembling, the process cost increases and the consumption is not small, so tens of thousands of broken diamonds are also common.
The price of broken diamonds is determined not only by 4C standard, but also by other conditions.
Different styles need different broken diamonds, so the cost of setting broken diamonds is different when deciding how many broken diamonds to use.
Rings and broken diamonds are decorations, so the number of broken diamonds needed for big rings and small rings will be different.
Quality of workmanship, the ones with good quality are more expensive.