Pearl zhēn zhū · 珍珠

Safety. Two things. First, it is essentially calcium carbonate: it does not dissolve in water, and the calcium load is relevant for anyone with hypercalcaemia, a history of calcium-containing kidney stones or impaired kidney function, and for anyone already taking calcium or vitamin D supplements. Second, cultured pearls are grown in water and molluscs concentrate heavy metals from it, so the same sourcing and assay point that applies to 珍珠母 and 牡蛎 applies here — pearl powder of unknown origin is not a product this site would vouch for. Cosmetic use on intact skin is the least demanding use; ingestion is a different matter. Human safety data in pregnancy and breastfeeding are insufficient. Not for self-directed internal use.