igneous
Quartz-bearing rock fragment, likely quartz vein in basalt or dark host rock
Quartz (SiO₂) with probable mafic host, possibly basalt or amphibolite
AI-generated identification · may be incorrectWhite to gray translucent quartz with glassy to dull luster, irregular fracture, and no obvious cleavage; Mohs hardness about 7. The dark portion may be fine-grained basaltic or amphibolitic material, but the image is insufficient for exact identification.
Identified More igneous →
Explore Quartz-bearing rock fragment, likely quartz vein in basalt or dark host rock in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
White to gray translucent quartz with glassy to dull luster, irregular fracture, and no obvious cleavage; Mohs hardness about 7. The dark portion may be fine-grained basaltic or amphibolitic material, but the image is insufficient for exact identification.
Formation & geological history
Likely formed when silica-rich fluids filled a fracture in older mafic rock; the host may be volcanic basalt or metamorphosed basalt. Its geological age cannot be determined from the photograph.
Uses & applications
Common quartz-bearing fragments have little market value and may be used as teaching or decorative specimens; quartz is important in glass, electronics, abrasives, and jewelry.
Geological facts
Quartz commonly forms white veins and survives weathering because it is hard and chemically resistant. The dark matrix could also be schist, gneiss, or slag, so a fresh surface and tests are needed.
Field identification & locations
Check whether the white material scratches glass and whether the dark matrix shows grains, foliation, or vesicles; acid testing and a hand lens may help. Quartz veins occur worldwide, especially in volcanic and metamorphic terrains.
