Agglutinate

Image Source: meteorites.wustl.edu

Common particle type in lunar regolith (photograph below). Agglutinates are small glassy breccias formed when micrometeorites (< 1 mm in diameter) strike the lunar regolith. During micrometeorite impacts, some of the regolith melts and some doesn’t, 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 H and He in the regolith causing bubbles in the glass. Agglutinates are typically 10s of μm to a few mm in size.

Some or all content above used with permission from J. H. Wittke.