sedimentary
Fossilized Fish Skeleton in Matrix
Vertebrata (Class: Actinopterygii), typically found in limestone or shale matrices
Hardness: 3-5 (calcite/apatite); Color: dark brown to black bones against tan or grey matrix; Luster: dull to sub-vitreous; Structure: biological skeletal preservation within a fine-grained sedimentary bed.
- Hardness
- 3-5 (calcite/apatite)
- Color
- dark brown to black bones against tan or grey matrix
- Luster
- dull to sub-vitreous
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Physical properties
Hardness: 3-5 (calcite/apatite); Color: dark brown to black bones against tan or grey matrix; Luster: dull to sub-vitreous; Structure: biological skeletal preservation within a fine-grained sedimentary bed.
Formation & geological history
Formation occurs through permineralization or carbonization where mineral-rich water replaces organic matter in an anaerobic environment; typical specimens are from the Eocene epoch (approx. 50 million years ago).
Uses & applications
Educational tools, museum displays, and private geological collecting. Highly valued for anatomical study of primordial life.
Geological facts
The Green River Formation in Wyoming is one of the world's most famous sites for such fossils, producing exceptionally detailed skeletons of fish like Diplomystus and Knightia.
Field identification & locations
Identified by symmetrical bilateral skeletal structures and articulated vertebrae embedded in flat sedimentary layers. Commonly found in quarries or basins known for fine-grained shale or limestone.
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