ˈ ̷ ̷ ̷ ̷ˌ ̷ ̷ noun
: a friable siliceous stone that is the residue of siliceous limestone from which the calcareous matter has been removed by the action of natural waters
ˈ ̷ ̷ ̷ ̷ˌ ̷ ̷ noun
: a friable siliceous stone that is the residue of siliceous limestone from which the calcareous matter has been removed by the action of natural waters
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012