sedimentary

Layered limestone, likely stromatolitic or microbial limestone

Limestone; predominantly calcite (CaCO₃), possibly biogenic micrite

AI-generated identification · may be incorrect

Light gray, fine-grained, strongly laminated and weathered, with dull to weakly earthy luster; calcite has Mohs hardness 3, rhombohedral cleavage, and specific gravity about 2.7. Effervesces visibly with dilute hydrochloric acid or vinegar if freshly exposed.

Identified August 23, 2026More sedimentary →

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At a glance

Common name: Layered limestone, likely stromatolitic or microbial limestone
Scientific name: Limestone; predominantly calcite (CaCO₃), possibly biogenic micrite
Category: sedimentary
Identified: August 23, 2026
Method: Standard

AI Estimated Value

About $5-$30 for a common hand specimen; distinctive confirmed stromatolitic slabs may sell for roughly $30-$200, depending on size, provenance, and preservation.

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

Forms by accumulation and cementation of carbonate mud or microbial mats in shallow marine or lacustrine environments. The image alone cannot establish geological age; similar laminated limestones range from Precambrian stromatolites to much younger sedimentary beds.

Uses & applications

Used for aggregate, cement, lime, building stone, and landscaping; attractive patterned pieces may be collected or cut as decorative stone, though this specimen appears rough and weathered.

Geological facts

The repeated wrinkled laminae may represent stromatolitic microbial growth, but could also reflect deformed bedding, algal structures, or weathered shale-like limestone. It is not possible to confirm a fossil or stromatolite identification from this photograph alone.

Field identification & locations

Look for carbonate reaction, powdery calcite-rich surfaces, and continuous sedimentary lamination; a steel nail generally does not scratch it easily, while a knife can. Common sources include marine carbonate platforms worldwide, especially regions with exposed limestone formations.