sedimentary
Chert
Silicon dioxide (SiO2)
AI-generated identification · may be incorrectHardness: 7; Color: gray, black, brown, red, green; Luster: waxy to dull; Crystal structure: microcrystalline quartz; Cleavage: none, exhibits conchoidal fracture
- Hardness
- 7
- Color
- gray, black, brown, red, green
- Luster
- waxy to dull
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Physical properties
Hardness: 7; Color: gray, black, brown, red, green; Luster: waxy to dull; Crystal structure: microcrystalline quartz; Cleavage: none, exhibits conchoidal fracture
Formation & geological history
Forms from the accumulation of siliceous marine micro-organisms or as a replacement mineral in carbonate rocks; can form in various geological ages
Uses & applications
Historically used for making stone tools and starting fires; today, sometimes used in construction or as an abrasive
Geological facts
Chert breaks with a conchoidal fracture, making it ideal for crafting sharp tools like arrowheads and scrapers.
Field identification & locations
Identify by its hardness (scratches glass), waxy luster, and conchoidal fracture. Commonly found in sedimentary basins and limestone deposits.
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