sedimentary
Chert
Silicon dioxide (SiO2)
AI-generated identification · may be incorrectHardness of 6.5-7 on Mohs scale. Colors can be varied, including brown, tan, gray, or banded. Waxy to dull luster. Microcrystalline quartz structure. Conchoidal fracture.
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Physical properties
Hardness of 6.5-7 on Mohs scale. Colors can be varied, including brown, tan, gray, or banded. Waxy to dull luster. Microcrystalline quartz structure. Conchoidal fracture.
Formation & geological history
Forms as a sedimentary rock from the accumulation of microscopic silica-rich organisms or through chemical precipitation of silica in limestone or chalk deposits.
Uses & applications
Historically used for making stone tools (arrowheads, scrapers) due to its conchoidal fracture. Sometimes used as a road surfacing material or for tumbling by lapidaries.
Geological facts
Flint and jasper are varieties of chert. The smooth, shiny surface of this specimen suggests it is wet or has been tumbled/polished by water.
Field identification & locations
Identified by its hardness (scratches glass), smooth waxy feel, and conchoidal fracture. Very common globally in sedimentary deposits and riverbeds.
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