Where is Basalt with Quartz Veins found?
Basalt (igneous rock) with Quartz (SiO2) veins
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Open the appBasalt with Quartz Veins occurs in specific geological environments. Knowing where to look, and in what kind of rock, is the difference between going home empty-handed and finding a great specimen.
Where to find Basalt with Quartz Veins
Columbia River Basalt Group, USA
Extensive flood basalts where hydrothermal alteration and quartz veining can be observed, particularly in areas of faulting or localized intrusions.
Deccan Traps, India
Another large igneous province with vast basalt flows, where secondary mineralization including quartz veins can occur.
Mid-ocean ridges and associated ophiolites
Basaltic oceanic crust is frequently hydrothermally altered, leading to the formation of quartz and other secondary minerals in veins.
Volcanic regions worldwide
Any region with significant basaltic volcanism can exhibit quartz veins if subsequent hydrothermal activity has occurred.
Collecting tips
- Look for contrasting colors. The dark basalt matrix will be sharply contrasted by the lighter, often white or milky, quartz veins.
- Check for hardness. Quartz (Mohs 7) is significantly harder than most minerals in basalt (e.g., plagioclase Mohs 6-6.5, pyroxene Mohs 5-6), so the veins will scratch steel and will not be scratched by a knife.
- Examine fracture patterns. Quartz will exhibit conchoidal fracture, while the basalt will have a more irregular or blocky fracture.
- Follow fracture zones. Quartz veins typically form in pre-existing fractures, faults, or shear zones within the basalt.
Quick Check
- Color:
- Dark (basalt) with white/milky (quartz) veins
- Luster:
- Dull to sub-vitreous (basalt) and vitreous (quartz)
- Streak:
- White (quartz) or grayish-white (basalt, though often not easily obtained due to hardness)
Explore Basalt with Quartz Veins
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