metamorphic

Quartz vein in greenstone/altered mafic rock

Quartz (SiO₂) with chlorite–epidote-rich metabasalt or greenstone

AI-generated identification · may be incorrect

Visible gray-white quartz is translucent, vitreous, and Mohs hardness 7, with no cleavage; the dark green host is fine-grained, likely chlorite/epidote-bearing metamafic rock, typically hardness about 5–7. The specimen has contrasting massive textures rather than obvious large crystals.

Identified September 4, 2026More metamorphic →

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Physical properties

Formation & geological history

Likely formed when silica-rich hydrothermal fluids filled fractures in basalt or gabbro, followed by low- to medium-grade metamorphism and greenschist-facies alteration. The exact geological age and locality cannot be determined from the photograph.

Uses & applications

Primarily a collector specimen; quartz-rich greenstone may also be used as decorative stone or aggregate, but this small piece has no practical industrial value.

Geological facts

The green color commonly reflects chlorite, epidote, actinolite, or altered pyroxene. A fresh quartz surface should scratch glass, while the green host may show a dull to weakly silky luster.

Field identification & locations

Look for a sharp quartz–greenstone boundary, glassy translucent quartz, and a dense dark-green host; streak, hardness, and acid testing can help distinguish carbonate-rich rocks. Similar material occurs in metamorphic belts worldwide, including the Appalachians, Alps, and western North America.