igneous
Quartz Vein in Host Rock
Quartz (SiO2) in Mafic or Sedimentary Matrix
Hardness: 7 (quartz vein) vs 4-6 (matrix); Color: White/creamy vein in brown/grey host; Luster: Vitreous to dull; Structure: Hexagonal crystal system (microcrystalline); Cleavage: None (conchoidal fracture); SG: 2.65
- Hardness
- 7 (quartz vein) vs 4-6 (matrix)
- Color
- White/creamy vein in brown/grey host
- Luster
- Vitreous to dull
Identified More igneous →
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Physical properties
Hardness: 7 (quartz vein) vs 4-6 (matrix); Color: White/creamy vein in brown/grey host; Luster: Vitreous to dull; Structure: Hexagonal crystal system (microcrystalline); Cleavage: None (conchoidal fracture); SG: 2.65
Formation & geological history
Formed through hydrothermal deposition where mineral-rich hot fluids filled fractures in a pre-existing rock body (host rock). This typically occurs in various geological ages during tectonic activity.
Uses & applications
Used primarily as an indicator for ore deposits (like gold). Common specimens are used for landscaping, road fill, or educational geological samples.
Geological facts
Quartz veins are the most common source of 'lode gold' deposits. They represent ancient plumbing systems where fluids moved through the Earth's crust.
Field identification & locations
Identify by the sharp contrast between the white crystalline band and the darker stony matrix. Found globally in mountainous or metamorphic terrains. Test for hardness; the white vein will scratch glass.
