If a gem doesn’t look after their gem well it can get scratched which leaves scars on the gems physical form. Having scratches and thus scars is considered very ugly in Homeworld culture since they are no longer “perfect” or look as intended. It is common with quartz soldiers, however they can just about get away with it cause of their job roles and fighting (plus since they’re all sisters they like to view it more as trophies and medals of honor from fights).
For other gems, especially ones who are meant to be pretty like Pearls, this can really lower their rank and so fourth. It can be smoothed out but is very expensive and dangerous so it is rarely fixed.
Cadet-For-Your-SpaceRescue 