sedimentary

Gray sandstone (likely arkosic or quartz-rich sandstone)

Clastic sandstone, predominantly quartz (SiO₂) with feldspar and rock fragments

AI-generated identification · may be incorrect

Fine- to medium-grained, gray-tan, dull to slightly gritty; individual grains are visible, with no obvious crystals or cleavage. Quartz hardness is 7 Mohs, but the rock’s bulk hardness varies with cement; typically specific gravity 2.2–2.7.

Identified August 29, 2026More sedimentary →

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At a glance

Common name: Gray sandstone (likely arkosic or quartz-rich sandstone)
Scientific name: Clastic sandstone, predominantly quartz (SiO₂) with feldspar and rock fragments
Category: sedimentary
Identified: August 29, 2026
Method: Standard

AI Estimated Value

About $5–$30 for an ordinary loose specimen; $50–$200 for an attractive, distinctive, or unusually large labeled specimen.

Not an official valuation

AI estimate for general interest only — not an appraisal. Actual value depends on condition, provenance, and market demand. Verify with a professional before buying, selling, or insuring.

This identification was generated by AI and may contain errors. Verify important details before relying on them — and never use an AI result to judge whether a specimen is safe to handle. Read the full disclaimer

Physical properties

Formation & geological history

Formed when sand accumulated, was compacted, and cemented by silica, calcite, or iron oxides in a river, beach, dune, or shallow-marine environment. Exact age cannot be determined from the image.

Uses & applications

Used as building stone, paving, wall cladding, aggregate, and sometimes decorative landscaping stone; generally low collector value.

Geological facts

Sandstone commonly preserves ripple marks, cross-bedding, mud cracks, and fossils. Gray coloration usually reflects quartz-rich sediment and limited iron-oxide staining.

Field identification & locations

Identify it by gritty sand-sized grains, layered or massive texture, and lack of interlocking visible crystals; dilute acid may fizz if calcite-cemented. Common worldwide in sedimentary basins.