sedimentary

Chert (Flint) with Quartz Vein

Silicon Dioxide (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 on Mohs scale. Color: Brown-orange (likely from iron oxide staining). Luster: Dull to waxy. Structure: Microcrystalline. Features: A distinct white quartz vein crossing the nodule.

Hardness: 6
Color: Brown-orange (likely from iron oxide staining)
Luster: Dull to waxy

Identified July 20, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 on Mohs scale. Color: Brown-orange (likely from iron oxide staining). Luster: Dull to waxy. Structure: Microcrystalline. Features: A distinct white quartz vein crossing the nodule.

Formation & geological history

Formed as nodules in limestone or chalk through the accumulation of silica-rich fluids. Common in the sedimentary basins of the French Alps/Vercors region (Drôme department).

Uses & applications

Historically used for tool making (arrowheads/scrapers) due to conchoidal fracture; modern use is primarily as landscaping rock or decorative specimen.

Geological facts

The brown coloring is likely due to the presence of limonite or goethite. The white line is a 'healed' fracture where secondary quartz crystallized within the chert nodule.

Field identification & locations

Identify in the field by its hardness (it will scratch glass) and its smooth, waxy texture compared to surrounding limestone. Very common in the Drôme region of France.