sedimentary or metamorphic

Sandstone or Quartzite with algae

Unknown specific, largely SiO2 with biological growth

AI-generated identification · may be incorrect

Hardness varies (6-7 for quartz-rich rocks). Tan, beige, grey color with bright green staining on the surface. Dull to earthy luster. Granular texture.

Identified August 25, 2026More sedimentary or metamorphic →

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Physical properties

Hardness varies (6-7 for quartz-rich rocks). Tan, beige, grey color with bright green staining on the surface. Dull to earthy luster. Granular texture.

Formation & geological history

Formed from compressed sand (sandstone) or heated/pressurized sandstone (quartzite). The green coloration is likely from recent biological growth (algae or moss) due to being in a damp environment.

Uses & applications

Common rock type used in construction and landscaping, but this specific piece is likely just a found stone collected for its shape or color.

Geological facts

The bright green color is almost certainly biological, not a mineral stain like malachite or epidote, given the texture and context of beach/river rocks.