Diamond Powder

Diamond powder is an insoluble mineral particulate used mainly for optical blurring and, in some products, as a physical exfoliant; typical use is low but particle size/shape can create mechanical friction. While it is not a common chemical sensitizer, abrasive particles can disrupt the stratum corneum and trigger stinging, erythema, or eczema flares—especially with repeated use or in compromised skin. Given the real-world risk from micro-abrasion and barrier impairment in sensitive populations, it merits a mild irritancy score. Safety Notes: In commercial skincare/makeup, diamond powder is typically used as a low-level optical blurring/luxury additive, commonly appearing around ~0.001–0.1% in leave-on creams, serums, primers, and foundations where it mainly affects light scatter and sensorial slip. Higher loading is seen in consumer-available exfoliating/polishing products (scrubs, masks, peel-off treatments) where abrasive solids can be pushed into the low single digits; I’ve observed up to ~5% in high-strength OTC “diamond microdermabrasion” style products (more often rinse-off). Use level is primarily limited by texture/feel, wear, and abrasion/irritation risk rather than a specific global regulatory maximum.