sedimentary
Yellow Chert
Microcrystalline Quartz (SiO2)
Hardness: 6.5-7 on Mohs scale; Color: honey-yellow, tan, or butterscotch; Luster: waxy to dull; Crystal structure: trigonal (microcrystalline); Cleavage: none (conchoidal fracture); Specific gravity: 2.65
- Hardness
- 6
- Color
- honey-yellow, tan, or butterscotch
- Luster
- waxy to dull
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Physical properties
Hardness: 6.5-7 on Mohs scale; Color: honey-yellow, tan, or butterscotch; Luster: waxy to dull; Crystal structure: trigonal (microcrystalline); Cleavage: none (conchoidal fracture); Specific gravity: 2.65
Formation & geological history
Formed by the accumulation of siliceous remains of marine organisms or through chemical precipitation of silica-rich fluids in sedimentary rock cavities, often during the Paleozoic or Mesozoic eras.
Uses & applications
Used historically for stone tools and arrowheads due to its sharp fracture edges. Today used as an abrasive, in landscaping, and as a collector's specimen.
Geological facts
This specimen is a variety of flint. It was a primary material for prehistoric humans to create fire-starting kits and hunting tools because of its predictable fracture patterns.
Field identification & locations
Look for a waxy texture and conchoidal (shell-like) fractures. Commonly found in riverbeds, glacial tills, and limestone formations throughout the Midwestern United States and Europe.
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