clean
Ruby clarity grades from low to high are si/vs2/vs1/vvs2/vvs1/IF, with the highest grade being IF and the highest value being if. The value of secondary VVS 1 is not low, but it will be much worse than IF level. The later, the lower the grade value.
incision
Cutting mainly starts from three aspects: directionality/symmetry and polishing. But there are no certain standards in these three aspects.
Weight (particle size)
The basic particle size of ruby is 5mm*7mm. If this work is done well, rubies with standard weight 1ct and less than 1ct are called "small particles", those with 3~5ct are called "large particles", and those with more than 5ct are extremely precious. Ok, you can use it often. As for what ruby is good, it can be said that the brighter and more uniform the color, the cleaner the interior, which is good.