These impacts gradually abrade sharp protrusions from the grains and give their surface a "frosted" luster.The width of this view is approximately 10 millimeters.
This photograph illustrates the size range of sand.
When the pumps are turned off, some of the sand grains become trapped within the fractures and prop them open.
This allows the flow of oil or gas from the rock unit to go into the fracture and into the well.
Grains in this image are about 0.50 millimeter in size. This sand from a dune near Christmas Lake, Oregon likely contains particles of ejecta produced by the eruption of Mount Mazama about 7700 years ago, which formed the caldera known today as Crater Lake.
The sand contains grains of pumice (white) and basalt (gray to black).
Frac sand is a very durable material capable of withstanding very high compressive forces.