Gem-Tac is a fantastic glue which dries clear.
Materials It Bonds:
Fabric, Gems, Glitter, Pearls, Plastic, Rhinestones, Studs, Leather, Vinyl, Wood
Permanent Dries Clear Non-Toxic Water Based Washable Water proof UVA Resistant Non-Flammable Shock Resistant Flexible, Never Brittle No unpleasant odor Now with precision tip caps
put a tiny dot of glue onto your costume, pick up your Crystal with the dotting tool and position on top of the glue.