fossil

Banded stromatolite (probable fossil limestone)

Microbial carbonate; commonly composed chiefly of calcite (CaCO₃), often classified as stromatolitic limestone

AI-generated identification · may be incorrect

Brown-to-cream, finely laminated and irregularly banded, with dull to slightly earthy luster; calcite hardness is 3 Mohs, with indistinct cleavage and specific gravity near 2.7. Dilute acid should fizz on fresh surfaces.

Identified September 13, 2026More fossil →

Explore Banded stromatolite (probable fossil limestone) 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: Banded stromatolite (probable fossil limestone)
Scientific name: Microbial carbonate; commonly composed chiefly of calcite (CaCO₃), often classified as stromatolitic limestone
Category: fossil
Identified: September 13, 2026
Method: Standard

AI Estimated Value

About $10–$75 for common specimens; $100–$500+ for large, well-preserved, legally sourced fossil pieces.

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

Formed when microbial mats trapped and cemented carbonate sediment in shallow marine or lake environments; many examples are Precambrian, roughly 3.5 billion–541 million years old, though younger forms occur.

Uses & applications

Used mainly as a fossil/geological collectible and educational specimen; dense stromatolitic limestone may occasionally be used decoratively or as building stone.

Geological facts

Stromatolites are among Earth’s oldest evidence of life and helped oxygenate the atmosphere through cyanobacterial photosynthesis.

Field identification & locations

Identify by persistent, millimeter-scale wavy laminations rather than ordinary bedding, often visible on multiple faces; common sources include Western Australia, Bolivia, Morocco, and Precambrian carbonate basins worldwide.