sedimentary

Chert (Likely Jasper)

Microcrystalline Quartz (SiO2)

AI-generated identification · may be incorrect

Hardness: 7 Mohs scale; Color: Honey-yellow, orange-brown, and white; Luster: Waxy to vitreous; Crystal Structure: Trigonal (Microcrystalline); Cleavage: None (Conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 Mohs scale
Color: Honey-yellow, orange-brown, and white
Luster: Waxy to vitreous

Identified June 15, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed via the accumulation of silica-rich microfossils on the seafloor or through the replacement of limestone by silica-saturated groundwater. This specimen displays the typical conchoidal fractures of cryptocrystalline silica.

Uses & applications

Historically used for making stone tools (arrowheads). Modern uses include lapidary work, jewelry (tumbled stones), and as a decorative landscaping rock.

Geological facts

Chert and its varieties like Jasper and Flint were among the first resources used by early humans for tools because of how they shatter into extremely sharp edges.

Field identification & locations

Identified in the field by its waxy luster, hardness (it will scratch glass), and smooth, shell-like (conchoidal) fracture surfaces. Commonly found in sedimentary rock layers or as nodules in limestone.