In optical mineralogy, if sediments are easily disaggregated, it is customary to spread the grains on a glass slide. This is often after the grains have been mechanically sorted according to grain size and density as measured. They are soon immersed in Canada balsam, or less permanently in some liquid. The mount is usually covered with a glass cover slip when ready to be evaluated under petrographic polarizing microscope used in optical mineralogy. Sand or finer grain sizes are suitable as loose-grain mounts for direct examination with the aid of polarizing microscopes for mineralogists.

 

            Crushed-grain mounts are prepared by either scraping mineral fragments from a crystl in a rock or mineral hand-specimen onto a glass slide, or by crushing a small mineral grain on a glass slide using a pocket knife. A suitable immersion liquid is introduced by capillary action from the edge of the cover slip which is placed over the fragments.