1.   In addition to studies using the modal composition of a sediment, other provenance determinations can be made from individual quartz grains.

2.   Minerals giving very low intensity emission, such as quartz grains, required many minutes or even hours of exposure with fast films.

3.   This phenomenon has been utilized for dating sedimentary deposits of quartz grains.

4.   He said he would be more convinced by shocked quartz grains, an additional sign of an extraterrestrial impact.