sedimentary
Green Chert
Microcrystalline Quartz (SiO2)
AI-generated identification · may be incorrectHardness: 7 on Mohs scale; Color: olive-green to dark grey-green; Luster: waxy to dull; Cleavage: none (conchoidal fracture); Specific gravity: ~2.65
- Hardness
- 7 on Mohs scale
- Color
- olive-green to dark grey-green
- Luster
- waxy to dull
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Physical properties
Hardness: 7 on Mohs scale; Color: olive-green to dark grey-green; Luster: waxy to dull; Cleavage: none (conchoidal fracture); Specific gravity: ~2.65
Formation & geological history
Formed through the accumulation and recrystallization of silica-rich biogenic sediments (like radiolarian tests) or chemical precipitation in marine environments.
Uses & applications
Historically used for stone tools, arrowheads, and spark-striking. Today used primarily in road aggregate, lapidary projects, and specimen collections.
Geological facts
Chert forms smoothly curved, sharp conchoidal fractures, making it one of the earliest materials humans used to manufacture cutting weapons and tools.
Field identification & locations
Identified in the field by its extreme hardness (scratches glass/steel easily), smooth conchoidal fracturing, and waxy luster. Common in bedded limestone and chalk formations worldwide.
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