sedimentary
Tumbled Flint / Chert
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Hardness: 6.5 - 7 on the Mohs scale. Color: Gray, tan, brown, beige, and off-white with smooth waxy-to-vitreous luster after tumbling. Cryptocrystalline structure with conchoidal fracture.
- Hardness
- 6
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Physical properties
Hardness: 6.5 - 7 on the Mohs scale. Color: Gray, tan, brown, beige, and off-white with smooth waxy-to-vitreous luster after tumbling. Cryptocrystalline structure with conchoidal fracture.
Formation & geological history
Formed through the accumulation of siliceous microscopic organisms (like radiolarians or diatoms) on the ocean floor or by chemical precipitation of silica in limestone and chalk deposits.
Uses & applications
Used historically for tool-making and fire-starting; today used in lapidary work, jewelry making, tumbled stone collections, and decorative crafts.
Geological facts
Chert and flint are among the first materials used by prehistoric humans to create sharp tools, arrowheads, and axes due to their predictable conchoidal fracture pattern.
Field identification & locations
Identified by its hard, dense composition, smooth waxy surface when polished, and absence of visible mineral grains. Commonly found in limestone beds, riverbeds, and gravel deposits worldwide.
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