sedimentary
Quartz Vein in Siltstone
Siltstone with Quartz (SiO2) inclusion
Hardness: 7 (Quartz) / 3-4 (Siltstone); Color: Dark grey and milky white; Luster: Dull/Earthy (matrix) and Vitreous (quartz); Structure: Fine-grained clastic matrix with crystalline vein.
- Hardness
- 7 (Quartz) / 3-4 (Siltstone)
- Color
- Dark grey and milky white
- Luster
- Dull/Earthy (matrix) and Vitreous (quartz)
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Physical properties
Hardness: 7 (Quartz) / 3-4 (Siltstone); Color: Dark grey and milky white; Luster: Dull/Earthy (matrix) and Vitreous (quartz); Structure: Fine-grained clastic matrix with crystalline vein.
Formation & geological history
Formed through the accumulation of silt-sized particles in aqueous environments, with a later hydrothermal event where silica-rich fluids filled fractures to form the quartz vein.
Uses & applications
Primarily used as decorative garden stones, educational specimens for geology, or low-cost aggregate in construction.
Geological facts
The sharp contrast between the light quartz and dark host rock is a classic example of hydrothermal activity within sedimentary layers, demonstrating how minerals can travel through solid rock via cracks.
Field identification & locations
Identify by its dual texture: a smooth, fine-grained dark base and a hard, crystalline white protrusion. Common in riverbeds and mountainous erosion zones.
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