chert
Concise Oxford English Dictionary © 2008 Oxford University Press:
chert /tʃəːt/
▶noun a hard, dark, opaque rock composed of silica (chalcedony) with an amorphous or microscopically fine-grained texture.
– derivatives
cherty adjective.
cherty adjective.
– origin C17 (orig. dial.): of unknown origin.
'chert' also found in these Oxford entries:
