Selecting the correct grade depends entirely on the end-use. For nail art and cosmetics, you must ensure the powder is cosmetic-grade (mica-based) and free from heavy metals. For automotive or industrial coatings, prioritize PVD (Physical Vapor Deposition) grade or high-purity metallic pigments that offer superior UV resistance and weatherability. Always verify the particle size (microns); finer particles (under 15μm) provide a smoother, mirror-like finish, while larger particles create a more glittered effect.