sedimentary

Sandstone with Vitrinite/Coal inclusions

Arenite with Carbonaceous inclusions

AI-generated identification · may be incorrect

Hardness: 6-7 (sandstone matrix), 2-3 (carbon inclusions); Color: Tan/Grey matrix with black/dark grey inclusions; Luster: Dull (matrix) to Vitreous/Sub-metallic (inclusions); Crystal structure: Clastic (matrix), Amorphous (carbon); Cleavage: None/Conchoidal in coal pieces

Hardness: 6-7 (sandstone matrix), 2-3 (carbon inclusions)
Color: Tan/Grey matrix with black/dark grey inclusions
Luster: Dull (matrix) to Vitreous/Sub-metallic (inclusions)

Identified June 10, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the accumulation of sand-sized mineral grains and organic plant matter in high-energy environments like rivers or deltas. Over millions of years, lithification preserves the sand as rock and carbonizes the plant material into vitrinite or coal.

Uses & applications

Sandstone is widely used in construction, architectural facades, and as an abrasive. The carbonaceous inclusions are of interest to geologists for paleo-environmental reconstruction.

Geological facts

The black inclusions are remnants of ancient plant material that have undergone carbonization. Sandstones with clear organic patterns can sometimes transition into petrified wood or contain significant fossilized imprints.

Field identification & locations

Identify in the field by the granular, sandpaper-like feel of the matrix and the presence of brittle, black, coal-like flecks or streaks. Commonly found in sedimentary basins and riverbeds near ancient forest deposits.