sedimentary

Glauconitic sandstone or altered volcanic rock

Glauconite-bearing quartz-rich rock; composition likely quartz (SiO₂), glauconite, feldspar, and iron oxides

AI-generated identification · may be incorrect

Hardness approximately 6–7 overall; dark olive-green to brown with rusty orange staining, granular texture, and mostly dull to glassy luster. Quartz grains may show no cleavage; exact identification requires a fresh surface and testing.

Identified August 28, 2026More sedimentary →

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At a glance

Common name: Glauconitic sandstone or altered volcanic rock
Scientific name: Glauconite-bearing quartz-rich rock; composition likely quartz (SiO₂), glauconite, feldspar, and iron oxides
Category: sedimentary
Identified: August 28, 2026
Method: Standard

AI Estimated Value

$5–$30 for a common hand specimen; $30–$100 if unusually attractive, labeled, or locality-specific.

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

Most consistent with sedimentary sandstone containing glauconite, formed in a shallow marine, low-oxygen environment; glauconite commonly forms during slow deposition over millions of years. The orange areas represent later oxidation of iron.

Uses & applications

Used mainly as a geological or lapidary specimen; glauconitic sandstone has limited construction use, while glauconite is used in soil amendments, water treatment, and potassium fertilizer.

Geological facts

Glauconite is an iron-potassium phyllosilicate responsible for the green color and commonly indicates marine deposition. The image alone cannot reliably distinguish it from chlorite-rich altered volcanic rock.

Field identification & locations

Look for rounded quartz grains, green earthy matrix, rusty weathering, and weakly friable texture; a streak, hardness, acid, and thin-section test would help. Common in marine sedimentary basins worldwide.