Filler (also called grist) is a petroleum- or coal-based @C01142@ fraction of a green, @C00842@ or formulation. Coarse particles, \(>0.425\ \mathrm{mm}\), are sometimes referred to as tailings; fine particles, \(<0.074\ \mathrm{mm}\), are referred to as flour. @G02684@ flour is also used as a filler.