Rice hulls
（重定向自Rice husk ash）
![Rice hulls](/Images/godic/202502/07/Rice_chaffs0917.jpg")
![The temples of the Batujaya Archaeological Site in Indonesia (5th century AD) were built with bricks containing rice hulls.](/Images/godic/202502/07/Bata_Candi-candi_Batujaya0917.JPG")
Rice hulls (or rice husks) are the hard protecting coverings of grains of rice. In addition to protecting rice during the growing season, rice hulls can be put to use as building material, fertilizer, insulation material, or fuel.