Earrings Round Diamond Grades

[malnik]

I got my finance a pretty round stone for her engagement ring and now she loves jewelry. I like to get her a set of earrings to match. I'm thinking of getting .50 to 0.60 ct round stones. My question is, would Premium cut / I color / si2 clarity be suffice for earrings?

 

[stone-cold11]

Case by case and who define premium and by what standard?