This feature is the diamond`s polish, it is also the only measurable feature which is independent to the formation process of the diamond but depends only on man made process and skill.
Important to know!
Polishing is the most important parameter influencing diamond appearance and reflectiveness.
It is better to buy a smaller diamond with better polish than a larger diamond with lousy polish.
The highest level of polish is known as triple EX or 3EX.
These facts and the entire article apply only to round diamonds.