sedimentary

Brown chert or silicified limestone fragment

Microcrystalline quartz (SiO₂), possibly occurring as chert; exact identification requires testing

AI-generated identification · may be incorrect

Dense, fine-grained, dull-to-waxy brown material with a smoothly weathered, wedge-like shape. Chert has Mohs hardness about 6.5–7, no cleavage, conchoidal fracture, and specific gravity near 2.6; the surface here appears slightly earthy, so silicified limestone is also possible.

Identified September 13, 2026More sedimentary →

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At a glance

Common name: Brown chert or silicified limestone fragment
Scientific name: Microcrystalline quartz (SiO₂), possibly occurring as chert; exact identification requires testing
Category: sedimentary
Identified: September 13, 2026
Method: Standard

AI Estimated Value

Usually $1–$10 as an ordinary specimen; higher only if it proves to be attractive jasper, fossiliferous material, or an archaeological artifact.

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 by silica replacing or accumulating within sedimentary carbonate beds, then weathered from the host rock. Such rocks commonly range from Paleozoic to Cenozoic in age; the image cannot establish a precise age.

Uses & applications

Chert is used for aggregate, roadstone, abrasion tools, and historically flaking tools; attractive pieces may be collected, though this specimen appears ordinary and unpolished.

Geological facts

The strongest diagnostic clue is hardness: it should scratch ordinary glass if it is chert. A streak test, acid reaction, and fresh fracture would distinguish chert from limestone.

Field identification & locations

The reported central-Iran location is geologically compatible with abundant sedimentary limestone and chert. Test with steel, glass, and a drop of dilute hydrochloric acid: no fizz plus glass-scratching favors chert; fizzing and easier scratching favor limestone.