metamorphic

Polished dark greenstone with quartz vein

Likely chlorite-rich metabasalt or greenschist with a quartz–feldspar vein

AI-generated identification · may be incorrect

Fine-grained, dark green-gray, weakly lustrous matrix with a contrasting cream vein; likely hardness 6–7 overall, with quartz at Mohs 7. Rounded and polished, so original cleavage and fabric are obscured; density approximately 2.8–3.0 g/cm³.

Identified September 4, 2026More metamorphic →

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Physical properties

Formation & geological history

Probably basalt altered during low- to medium-grade regional metamorphism, with silica-rich fluids later filling a fracture to form the pale vein. Such rocks commonly formed in ancient oceanic crust and metamorphic belts, typically from Paleozoic to Precambrian settings.

Uses & applications

Suitable as a decorative worry stone, paperweight, or lapidary material; not usually valuable as gemstone-grade material. Comparable pieces are collected for attractive veining and smooth polish.

Geological facts

The pale band is most plausibly quartz, though cream feldspar or carbonate is possible. A glassy or sugary vein texture and greater scratch resistance than the matrix would support quartz identification.

Field identification & locations

Commonly found in metamorphic belts, greenstone terrains, and river gravels. Field checks include a streak test, hardness test, and acid test: quartz will not react with dilute hydrochloric acid, whereas carbonate vein material may fizz.