Agglutinates are a common type of particle found in lunar regolith. Agglutinates are small glassy breccias formed when micrometeorites (< 1 millimeter in diameter) strike the lunar regolith. During micrometeorite impacts, some of the regolith melts and some does not, so the final product is a glass with entrained mineral and rock fragments. The glass often shows flow features and vesicles (gas bubbles). Impacts liberate solar-wind-implanted hydrogen and helium in the regolith causing bubbles in the glass. Agglutinates are typically tens of microns to a few mm in diameter.