Main Entry:

chert

Pronunciation:

\ˈchərt, ˈchat\

Function:

noun

Etymology:

origin unknown

Date:

1679

: a rock resembling flint and consisting essentially of a large amount of fibrous chalcedony with smaller amounts of cryptocrystalline quartz and amorphous silica

— cherty \ˈchər-tē, ˈcha-\ adjective