metamorphic

Dark gray veined metamorphic rock

Likely marble or quartzite; exact identification requires hardness and acid tests

AI-generated identification · may be incorrect

Dark gray, fine- to medium-grained, subrounded cobble with abundant white mineral veins, probably calcite or quartz. Likely hardness Mohs 3 if marble or 7 if quartzite; nonmetallic luster and massive texture.

Identified September 20, 2026More metamorphic →

Explore Dark gray veined metamorphic rock in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed when limestone or quartz-rich sandstone was recrystallized by heat and pressure during regional or contact metamorphism. Its precise geological age and source cannot be determined from the image.

Uses & applications

Common varieties are used as decorative stone, aggregate, paving, and architectural material; attractive pieces may be collected but this specimen appears ordinary.

Geological facts

White cross-cutting veins indicate later mineral-filled fractures. A drop of dilute hydrochloric acid that fizzes suggests calcite-rich marble; scratching glass strongly suggests quartzite.

Field identification & locations

Look for interlocking crystals, absence of bedding, and vein networks. Marble is common in metamorphic belts worldwide; quartzite occurs wherever sandstone has been metamorphosed.