Strength-Density Relations in Particulate Silicates of Complex Shape and Their Possible Lunar Significance

Some terrestrial particulate silicate rocks with complex particle shapes have internal friction angles over 45° and cohesion of about 0.1 newton per square centimeter at bulk densities of 0.6 to 0.8 gram per cubic centimeter. Mechanical and other properties of the lunar surface layer, observed with spacecraft, may be consistent with a low bulk density and complex reentrant shapes for the fine particles.