Apparatus and technique are described for quantitative removal of fine particles from crushed sandstones. The separation apparatus combines ultrasonic energy with elutriation and filtration techniques. The cleaning effect of the ultrasonic energy permits separation of much fine material from crushed sandstone samples which otherwise is not removed because of agglomeration and adhesion to sand grains. The ultrasonic elutriation technique recovered about 50 percent more fine material from disaggregated sandstone than wet sieving. An electronic particle counter is used for determining the size distribution of the particulate matter separated. Good reproduction of data is obtained with the counter over the range from 2 to 25 microns. Chemical and X-ray mineralogical analyses of the fine portion of natural sediments are enhanced by use of the separation techniques. Sufficient quantities of particles can be obtained within a few hours of unattended operation to permit analyses for several geologically important elements.