sedimentary
Ferruginous Sandstone (with Pyrite/Gold associations)
Ferruginous Arenite (SiO2 + Fe2O3)
Hardness: 6-7 (individual grains); Color: Brown, rusty orange, grey; Luster: Dull/Earthy matrix with metallic inclusions; Structure: Clastic; Cleavage: None.
- Hardness
- 6-7 (individual grains)
- Color
- Brown, rusty orange, grey
- Luster
- Dull/Earthy matrix with metallic inclusions
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Physical properties
Hardness: 6-7 (individual grains); Color: Brown, rusty orange, grey; Luster: Dull/Earthy matrix with metallic inclusions; Structure: Clastic; Cleavage: None.
Formation & geological history
Formed by the lithification of sand grains cemented together by iron oxides (hematite or limonite). These often form in fluvial or shallow marine environments where iron-rich waters circulate through porous sediment.
Uses & applications
Used in construction as a building stone or road base; sometimes used as an indicator for precious metal prospecting if metallic inclusions are present.
Geological facts
The 'golden' flakes visible are likely iron sulfides (pyrite) or muscovite mica, but in specific geological districts, these iron-rich conglomerates are studied as potential sources for placer gold.
Field identification & locations
Identify in the field by its sandy texture and heavy staining with rust colors. Found commonly in sedimentary basins and riverbeds where weathering concentrates iron.
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