sedimentary
Chert
Microcrystalline quartz (SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, typically dark gray or black with conchoidal fracture and a waxy luster.
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Physical properties
Hardness of 7 on the Mohs scale, typically dark gray or black with conchoidal fracture and a waxy luster.
Formation & geological history
Formed via the chemical precipitation of silica from seawater or the replacement of limestone during sedimentary diagenesis.
Uses & applications
Historically used for making stone tools and weapons due to its sharp fracture edges; occasionally used for decorative landscaping.
Geological facts
Ancient humans prized chert and flint for knapping into arrowheads and spear points because of its predictable fracture mechanics.
Field identification & locations
Identify in the field by its dark color, extreme hardness, sharp edges, and conchoidal fracture patterns. Found worldwide in sedimentary rock formations.
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Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
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