sedimentary
Chert
Silicon dioxide (SiO2)
AI-generated identification · may be incorrectHardness: 7 (Mohs), Color: light gray to greenish or beige, Luster: waxy to dull, Crystal structure: microcrystalline or cryptocrystalline, Cleavage: none (conchoidal fracture), Specific gravity: 2.5-2.8
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Physical properties
Hardness: 7 (Mohs), Color: light gray to greenish or beige, Luster: waxy to dull, Crystal structure: microcrystalline or cryptocrystalline, Cleavage: none (conchoidal fracture), Specific gravity: 2.5-2.8
Formation & geological history
Formed from silica-rich fluids or biological remains (like radiolarians or diatoms) accumulating and crystallizing in sedimentary environments, often limestone or chalk.
Uses & applications
Historically used for making stone tools (flintknapping) due to its conchoidal fracture. Sometimes used as an aggregate in construction.
Geological facts
Chert includes varieties like flint, jasper, and agate depending on color and formation. It was essential for early human survival for tools and fire starting.
Field identification & locations
Identify by its hardness (scratches glass), waxy luster, and conchoidal fracture. Common in sedimentary rock formations. Look for sharp edges on broken pieces.
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