igneous
Quartz Vein in Basalt or Mafic Rock
Silicon Dioxide (SiO2) vein in volcanic/mafic matrix
Hardness of 7 on the Mohs scale for the white quartz portion, while the dark matrix is harder to scratch depending on mineral composition (typically 5-6). Color is stark white/creamy for the quartz and dark grey/black for the host rock. Luster is vitreous to greasy for the quartz and dull for the dark rock.…
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Physical properties
Hardness of 7 on the Mohs scale for the white quartz portion, while the dark matrix is harder to scratch depending on mineral composition (typically 5-6). Color is stark white/creamy for the quartz and dark grey/black for the host rock. Luster is vitreous to greasy for the quartz and dull for the dark rock. Cryptocrystalline to macrocrystalline structure.
Formation & geological history
Formed through hydrothermal processes where silica-rich fluids filled fractures or voids in cooling volcanic or mafic host rocks millions of years ago.
Uses & applications
Used primarily as decorative landscape stone, lapidary work, and mineral collecting.
Geological facts
Quartz veins are very common geological features found globally, often hosting precious metals like gold in mineralized zones.
Field identification & locations
Easily identified by the striking contrast between the white quartz and the dark host rock. Common in mountainous regions, riverbeds, and areas with past volcanic or tectonic activity.
