Silcrete
Silcrete is comprised of nearly 100% silica, generally of low permeability, commonly having a conchoidal fracture and vitreous lustre. Although some siliceous pans have been previously described as silcrete, unless they have the above properties, they would be more reliably described as siliceous pans.
This silica cemented material is extremely hard. It commonly has a shiny, slightly glittery surface and has a characteristic ring sound when hit firmly with a geology hammer. Care needs to be taken when testing for the ring sound, as excessive force may cause sharp splinters to fly off the silcrete.
Photo credit: Ben Harms.
Photo credit: Atlas of regolith materials of Queensland (2008), CRC LEME.
Photo credit: Atlas of regolith materials of Queensland (2008), CRC LEME.