Silica sand is a type of sand that contains silica, a naturally occurring mineral that is commonly used in the oil and gas industry for hydraulic fracturing, or "fracking". Silica sand is used in hydraulic fracturing to prop open underground rock formations and allow oil and gas to flow more freely. The sand is mixed with water and chemicals and then injected into the well at high pressure. The pressure fractures the rock, and the sand holds the fractures open, allowing the oil and gas to flow out.

The quality of the silica sand used in hydraulic fracturing is important, as it can affect the efficiency of the process. The sand must be strong enough to withstand the pressure of the injection and also have the right size and shape to create the necessary fractures.