sedimentary

Brown Quartz (Jasper or Chert)

Silicon Dioxide (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 Mohs. Color: Brown, tan, or reddish-brown. Luster: Vitreous to waxy. Crystal Structure: Hexagonal/Microcrystalline. Cleavage: None (conchoidal fracture). Specific Gravity: 2.6-2.7.

Hardness: 6
Color: Brown, tan, or reddish-brown
Luster: Vitreous to waxy

Identified June 3, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 Mohs. Color: Brown, tan, or reddish-brown. Luster: Vitreous to waxy. Crystal Structure: Hexagonal/Microcrystalline. Cleavage: None (conchoidal fracture). Specific Gravity: 2.6-2.7.

Formation & geological history

Forms primarily through the accumulation of microcrystalline silica in marine or freshwater environments. Often found as nodules in limestone or as replacement material in fossils.

Uses & applications

Used primarily in lapidary work for making cabochons, beads, and tumbled stones. Historically used for making tools and arrowheads due to its sharp fracture edges.

Geological facts

This specimen appears to be a common microcrystalline variety of quartz. Quartz is the second most abundant mineral in Earth's continental crust and is incredibly resistant to chemical weathering.

Field identification & locations

Identify in the field by its hardness (it should scratch glass), its smooth conchoidal fracture, and lack of visible crystal grains. Commonly found in riverbeds, gravel pits, and sedimentary outcrops.