sedimentary
Knightia Fossil in Limestone
Knightia eocaena in micritic limestone
Hardness: 3-4 (matrix); Color: Tan/buff matrix with dark brown fossils; Luster: Dull/earthy; Fine-grained sedimentary structure with visible skeletal carbonizations.
- Hardness
- 3-4 (matrix)
- Color
- Tan/buff matrix with dark brown fossils
- Luster
- Dull/earthy
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Physical properties
Hardness: 3-4 (matrix); Color: Tan/buff matrix with dark brown fossils; Luster: Dull/earthy; Fine-grained sedimentary structure with visible skeletal carbonizations.
Formation & geological history
Formed during the Eocene epoch (approx. 52 million years ago) in the Green River Formation. Fossilization occurred in a freshwater lake system (Fossil Lake) where fish died and were buried in low-oxygen fine silt.
Uses & applications
Educational specimens, museum displays, home decor, and high-value items for fossil collectors.
Geological facts
Knightia is the state fossil of Wyoming. These specimens are often so well-preserved that soft tissues and individual scales can be observed under a microscope.
Field identification & locations
Identify in the field by looking for layered shale or limestone outcroppings in southwestern Wyoming. Collectors look for 'splits' along bedding planes that reveal dark organic silhouettes of fish.
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