sedimentary
Chert Arrowhead (Jasper)
Microcrystalline Quartz (SiO2)
Hardness: 6.5-7 Mohs; Color: reddish-brown; Luster: waxy to vitreous; Structure: cryptocrystalline; Breakage: conchoidal fracture.
- Hardness
- 6
- Color
- reddish-brown
- Luster
- waxy to vitreous
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Physical properties
Hardness: 6.5-7 Mohs; Color: reddish-brown; Luster: waxy to vitreous; Structure: cryptocrystalline; Breakage: conchoidal fracture.
Formation & geological history
Formed through the accumulation of silica-rich fluids or organic remains (like radiolarians) in sedimentary environments, later hardening into dense rock. Date back millions of years.
Uses & applications
Historically used for tools and weapons; modernly used for decoration, jewelry, and educational collectibles.
Geological facts
Chert is one of the most durable stones used by ancient civilizations for knapping due to its predictable conchoidal fracturing which creates razor-sharp edges.
Field identification & locations
Identified by its waxy texture, extreme hardness (can scratch glass), and the shell-like curved patterns (conchoidal flakes) left by the knapping process.
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