metamorphic

Weathered iron-rich quartzite or chert nodule

Quartzite/chert, predominantly microcrystalline SiO₂ with iron-oxide staining

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; off-white to gray interior with reddish-brown weathering rind, dull to slightly waxy luster, and no obvious cleavage. The rounded, dense form suggests a silica-rich nodule, though the image cannot confirm texture or composition.

Identified September 2, 2026More metamorphic →

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At a glance

Common name: Weathered iron-rich quartzite or chert nodule
Scientific name: Quartzite/chert, predominantly microcrystalline SiO₂ with iron-oxide staining
Category: metamorphic
Identified: September 2, 2026
Method: Standard

AI Estimated Value

Approximately $1–$15 for a common hand specimen; higher only if provenance, unusual patterning, or confirmed gemstone quality is present.

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

Likely formed from silicified sediment or quartz-rich sandstone, then exposed and rounded by weathering and transport; its precise geological age and setting are indeterminate from the photograph.

Uses & applications

Mostly a collector or teaching specimen; quartzite can be used as aggregate and building stone, while chert is used for tools and minor decorative purposes.

Geological facts

Iron oxides commonly produce the reddish-brown rind and patches. A fresh broken surface would help distinguish granular quartzite from smoother, waxy chert.

Field identification & locations

Look for glassy grains and sugary texture in quartzite versus a uniform, conchoidally fracturing surface in chert; it may occur in river gravels, exposed bedrock, or glacial deposits.