sedimentary

Quartz (Jasper / Chert)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale. Color: Brownish-orange with darker inclusions. Luster: Vitreous to waxy. Crystal structure: Trigonal (microcrystalline/cryptocrystalline quartz). Cleavage: None (exhibits conchoidal fracture). Specific gravity: 2.60 - 2.65.

Hardness: 7 on Mohs scale
Color: Brownish-orange with darker inclusions
Luster: Vitreous to waxy

Identified July 28, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the precipitation of silica from aqueous solutions or the accumulation of silica-rich skeletal remains of micro-organisms, typically occurring in sedimentary environments or as a secondary replacement mineral in limestones.

Uses & applications

Used for lapidary work, decorative objects, tumbled stones, jewelry, and mineral collecting.

Geological facts

Cryptocrystalline varieties of quartz like jasper and chert have been used by humans for hundreds of thousands of years to create stone tools, arrowheads, and blades due to their conchoidal fracture.

Field identification & locations

Can be identified by its high hardness (scratches glass), waxy luster, and lack of cleavage with smooth conchoidal breakage. Common worldwide in riverbeds, glacial tills, and sedimentary rock formations.