I covered my bug toe in crystal and then about 3 layers of Brisa gel and this didn't dull them I think it made them sparkle more!
Try shellac base coat then put ur crystals on top of that then cure it then put shellac top coat over and cure it! That will help them keep put for weeks. I also put shellac top coat over nail art and it really does make it last 2week! Clients think its fab as nail art usually chip after 3 days. Do u currently use shellac? Xx