RE:RE:RE:Hold the line!Yes, it's predominantly white silica sand that's used. Some brown silica (or local sands) are used if the pressures in the formation are low enough. In the high pressure areas they will go to either a resin coated natural sand or into a manufactured ceramic sand. Most of the white sands come from the Midwest, Wisconsin area. There's a few sand mines in Texas and other states that also have capabilities but low quality sand cab plug up a pump and/or can create slugs, which will crater a fluid end or worse, a power end on a Frac pump.