How to use in-sentence of “chert”:
+ Since 1980, the chert has been examined by the Münster group, and from 1987 by Aberdeen University.
+ The reliability of microscopic use-wear analysis on Monterey chert tools.
+ People used chert to make arrow heads because it was hard and sharp when broken.
+ The Rhynie chert is a sedimentary rock.
+ Fossils of cyanobacterial mats are found throughout the Archean—becoming especially common late in the eon—while a few other probable bacteriumbacterial fossils are known from chert beds.
