sedimentary
Stromatolite
Biogenic sedimentary rock / CaCO3
AI-generated identification · may be incorrectHardness 3-4 on Mohs scale, typically gray or brown with layered domed structures, dull luster.
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Physical properties
Hardness 3-4 on Mohs scale, typically gray or brown with layered domed structures, dull luster.
Formation & geological history
Formed by the trapping and binding of sediment by colonies of micro-organisms, primarily cyanobacteria, dating back billions of years.
Uses & applications
Valuable index fossils for studying early Earth environments and popular in educational and collector displays.
Geological facts
Stromatolites represent some of the oldest records of life on Earth, responsible for producing oxygen in the early atmosphere.
Field identification & locations
Identify by distinctive layered, concentric domed structures in marine sedimentary layers worldwide.
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