When sourcing crystal party bags, the grade of the rhinestones is paramount; prioritize AAA grade glass crystals or K9 crystals over plastic acrylics to ensure high refractive indices and long-lasting sparkle. Examine the setting technique, favoring hand-set prong settings or high-strength adhesive bonding that prevents stones from falling off during use. Additionally, check the metal frame construction, ensuring it is made of electroplated zinc alloy or brass to prevent oxidation and ensure a smooth, snag-free finish that won't damage delicate evening wear.