When sourcing small rice pearls (typically 2mm to 5mm), the primary quality indicators are Luster, Surface Purity, and Nacre Thickness. High-quality rice pearls should exhibit a sharp, mirror-like reflection rather than a dull or chalky appearance. You must verify the surface grade (AAA to A); for high-end jewelry, ensure that at least 90-95% of the surface is free of pits or rings. Additionally, check the uniformity of the 'rice' shape across the strand to ensure consistency for mass-produced jewelry designs.