sedimentary

Chert or silicified sedimentary fragment (tentative)

Microcrystalline quartz (SiO₂), possibly silicified limestone or fossil-bearing chert

AI-generated identification · may be incorrect

Tan to cream, dull-to-waxy luster, apparently very fine-grained with irregular conchoidal-looking edges; Mohs hardness about 6.5–7 if chert. Cleavage absent; specific gravity roughly 2.6. The shape may be naturally weathered or intentionally flaked/carved, but the image does not show diagnostic crystal faces.

Identified August 30, 2026More sedimentary →

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At a glance

Common name: Chert or silicified sedimentary fragment (tentative)
Scientific name: Microcrystalline quartz (SiO₂), possibly silicified limestone or fossil-bearing chert
Category: sedimentary
Identified: August 30, 2026
Method: Standard

AI Estimated Value

$1–$20 for a common fragment; approximately $25–$200+ if proven fossiliferous, unusually patterned, or archaeologically authenticated.

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

Chert forms when silica replaces or precipitates within marine or lacustrine sediment, commonly during diagenesis; silicification can occur from Paleozoic through Cenozoic deposits. Around 43°N, 108°W, sedimentary rocks and silicified material are regionally plausible.

Uses & applications

Common chert is used historically for knapping tools and occasionally as aggregate or decorative stone; attractive varieties are collected, polished, or made into lapidary objects.

Geological facts

The pointed, flaked-looking profile could resemble a worked stone artifact, but use-wear and deliberate flaking cannot be confirmed from this photograph. It could also be a weathered fossil or silicified fragment.

Field identification & locations

Test cautiously with a steel knife or glass: true chert should scratch glass and resist a knife. A visible reaction to dilute acid would suggest limestone rather than pure chert. Common pieces are usually worth $1–$20; unusual fossils or confirmed artifacts may be worth much more.