sedimentary

Chert or flint with chalcedony/quartz veins

Microcrystalline silica: primarily quartz (SiO₂), including chalcedony; possible fossiliferous limestone or silicified material

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; cream, tan, gray, and white with waxy to dull luster. Massive, fine-grained, and irregularly fractured; the visible ridges may be fossil or replacement textures rather than crystals.

Identified August 10, 2026More sedimentary →

Explore Chert or flint with chalcedony/quartz veins in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

At a glance

Common name: Chert or flint with chalcedony/quartz veins
Scientific name: Microcrystalline silica: primarily quartz (SiO₂), including chalcedony; possible fossiliferous limestone or silicified material
Category: sedimentary
Identified: August 10, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a common hand specimen; $30–$100+ if confirmed as an attractive or scientifically significant silicified fossil.

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 likely formed when silica-rich fluids replaced carbonate sediment or accumulated as biogenic silica in sedimentary environments, generally during the Paleozoic–Cenozoic. Exact age and identification require locality and testing.

Uses & applications

Used historically for sharp tools and occasionally as decorative stone, lapidary material, or curiosities; this specimen appears primarily of collector interest.

Geological facts

Chert commonly breaks with conchoidal fracture and can resemble jasper, chalcedony, silicified limestone, or fossil material. The sculpted-looking surface may represent a silicified fossil or weathered replacement texture.

Field identification & locations

Check for a glassy/conchoidal break, no reaction to dilute hydrochloric acid, and ability to scratch glass; a streak test is usually white. Common worldwide in limestone and sedimentary formations; locality is essential for distinguishing chert from silicified fossil limestone.