sedimentary

Chert (Jasper variety)

Microcrystalline Quartz (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs). Color: Reddish-brown, tan, or orange-pink. Luster: Waxy to dull. Crystal Structure: Trigonal (microcrystalline/cryptocrystalline). Cleavage: None (conchoidal fracture). Specific Gravity: 2.6 – 2.9.

Hardness: 6
Color: Reddish-brown, tan, or orange-pink
Luster: Waxy to dull

Identified April 6, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the accumulation of silica-rich microfossils or chemical precipitation from silica-rich fluids in sedimentary environments. Common in marine deposits and can vary in age from Precambrian to Cenozoic.

Uses & applications

Historically used for stone tools (knapping) due to its sharp edges. Modernly used for lapidary work, jewelry, and as decorative stone in gardens.

Geological facts

Jasper is an opaque variety of chalcedony. The reddish hues are typically caused by iron oxide (hematite) inclusions within the silica structure.

Field identification & locations

Identify in the field by its smooth, shell-like (conchoidal) fracture and its ability to scratch glass. It is commonly found in stream beds, beaches, and sedimentary basins worldwide.