Why Are there two numbers for that grit size? Equally the ANSI grit standard while in the US along with the FEPA grit standard in Europe relate to an average particle size, but use slightly different measurement methods. Silicon is actually a naturally occurring element found in many forms on https://www.quora.com/profile/Trevor-Flatcher-2/Comparative-analysis-of-silicon-carbide-and-traditional-silicon-materials-Silicon-Carbide-vs-Traditional-Silicon-Mater-1