Chert
/tʃɜːrt/noun
A hard, fine-grained sedimentary rock composed mainly of microcrystalline silica.
Did you know?“Chert” is an etymological mystery: major dictionaries classify its origin as uncertain, even though geologists have used the term for centuries.
Etymological Timeline
Late Middle English?
Middle English
cherte
“A possible early form associated with a hard stone; the identification and origin remain uncertain.”
17th Century
English
chert
“A term for a hard, flintlike stone appears in English usage.”
1670s
English
chert
“The word is recorded in geological and mineral descriptions, though its source is still unexplained.”
18th Century
English
chert
“The term becomes established for dense, flintlike varieties of silica-rich rock.”
Modern English
English
chert
“A hard sedimentary rock made chiefly of microcrystalline or cryptocrystalline silica.”