Garnet is a chemically inert, non-metallic, high density, high hardness mineral. Garnet's chemical and abrasive resistance make it an ideal lower filtration layer of down-flow multi-layer water filtration systems. It's high density provides stability within your filter bed. It is often with other medias such as Pyrolox, Calcite, Sand, Greensand, or Birm. When used in combination with other filter medias, higher flow rates, higher loading, and better filtration can be achieved.