sedimentary
Siltstone with Quartz Vein
Siltstone (composed of Quartz and Clay minerals) with a hydrothermal Quartz vein (SiO2)
Hardness: 6-7 (vein), 4-6 (matrix); Color: Earthy reddish-brown matrix with a white/cream vein; Luster: Dull/earthy matrix, vitreous vein; Structure: Clastic fine-grained sediment
- Hardness
- 6-7 (vein), 4-6 (matrix)
- Color
- Earthy reddish-brown matrix with a white/cream vein
- Luster
- Dull/earthy matrix, vitreous vein
Identified More sedimentary →
Explore Siltstone with Quartz Vein in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6-7 (vein), 4-6 (matrix); Color: Earthy reddish-brown matrix with a white/cream vein; Luster: Dull/earthy matrix, vitreous vein; Structure: Clastic fine-grained sediment
Formation & geological history
Formed through the lithification of silt-sized particles in a low-energy aquatic environment. The white band is a secondary hydrothermal vein formed when silica-rich fluids filled a crack in the rock. Likely Mesozoic in age given the regional geology of SE France.
Uses & applications
Generally used as fill material or aggregate in construction. High-quality siltstones are sometimes used for flagstone or minor architectural details.
Geological facts
The location (44.7°N, 5.2°E) is in the Drôme region of France, which is part of the Alpine foreland. This area is rich in sedimentary sequences from the Cretaceous and Jurassic periods, where such veined rocks are very common due to Alpine tectonic stresses.
Field identification & locations
Identify by its fine, gritty texture (smoother than sandstone) and the hard, crystalline nature of the white band which cannot be scratched by a steel knife. Found commonly in riverbeds and mountain slopes in the French Prealps.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sedimentary Sandstone
Arenite (Sedimentary Rock)
sedimentary
Fossiliferous Concretion
Septarian Concretion containing Brachiopods/Crinoids
fossil
Shale
Shale (clastic sedimentary rock)
sedimentary
Brown Sandstone (River Rock)
Arenite
sedimentary
Shale
Argillaceous sedimentary rock
sedimentary