In petrology, the term "chert" refers generally to all chemically precipitated sedimentary rocks composed primarily of microcrystalline, cryptocrystalline and microfibrous silica. Most cherts are nearly pure silica, with … See more

The cryptocrystalline nature of chert, combined with its above average ability to resist weathering, recrystallization and metamorphism has made it an ideal rock for preservation of … See more

There are numerous varieties of chert, classified based on their visible, microscopic and physical characteristics. Examples are: See more

• Photo & note re: Fig Tree Formation
• Microphotographs of Fig Tree fossils
• Schopf, J.W. (1999) Cradle of Life: The Discovery of Earth's Earliest Fossils, Princeton University Press, 336 p. ISBN 0-691-00230-4 See more

Chert is of only modest economic importance today as a source of silica (quartz sand being much more important.) However, chert deposits may be associated with valuable deposits of iron, uranium, manganese, phosphorite, and petroleum See more

• Petrology – Branch of geology that studies the formation, composition, distribution and structure of rocks
• Archaeology – Study of human activity via material culture See more