Optical and high-frequency electrical properties of the lunar sample

Reflectivity and polarization laws for the powder sample and its spectrum are close to the mean for the lunar maria. Solid samples show a marked absorption feature at 1 micron. The low albedo appears to be due to a surface coating on dust grains rather than to volume absorption. The high-frequency electrical properties resemble those of a fine powder made from typical dense terrestrial rocks and are consistent with previous estimates from ground-based radar observations. The differential mass spectrum is almost constant from 100 micron particles down to 0.1 micron particles; most particles are smaller than 0.3 micron. Their shapes disclose a variety of processes of generation.