- (geology, uncountable) Massive, usually dull-colored and opaque, quartzite, hornstone, impure chalcedony, or other flint-like mineral.
- (countable) A flint-like tool made from chert.
Generally, in mineralogy and geology, a chert does not have a conchoidal fracture. In North American archeology the term chert occasionally is still used for various siliceous minerals (including flint) that have a conchoidal fracture; this leads to confusion between the terms flint and chert in some archeology texts.
- “Chert” in David Barthelmy, Webmineral Mineralogy Database, 1997–.
- chert mindat.org, Hudson Institute of Mineralogy, accessed 29 August 2016