Silt

Silt is a fine particulate mineral sediment used in masks/cleansers primarily for absorbency and mild physical exfoliation, typically at moderate-to-high percentages. While chemically inert, its particle load can mechanically irritate reactive or eczema-prone skin, especially with rubbing, compromised barriers, or concurrent use of other actives. Clinically, mineral particulates more often cause irritant (not allergic) reactions via friction and barrier disruption, so I score it as mild rather than inert for patient safety. Safety Notes: In commercial skincare, silt (fine mineral/earth particulate used for absorbency, exfoliation, and a “mud” sensorial claim) is sometimes included at very low levels (~0.1–1%) in cleansers, masks, and scrubs primarily for marketing/texture and mild oil-control. The highest consumer-available levels are seen in rinse-off mud/clay masks and body scrubs where the formula is largely mineral solids (often 20–60% total mineral phase, with silt as a major component), while true leave-on products typically stay much lower (generally <1–5%) due to grittiness, residue, and stability/settling constraints.