sedimentary
Fossiliferous Limestone
Bioclastic Limestone (CaCO3)
Hardness: 3-4 (Mohs scale); Color: Buff, tan, grey; Luster: Dull to earthy; Structure: Clastic/Biogenic texture with visible fossil fragments; Cleavage: None (none-foliated)
- Hardness
- 3-4 (Mohs scale)
- Color
- Buff, tan, grey
- Luster
- Dull to earthy
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Physical properties
Hardness: 3-4 (Mohs scale); Color: Buff, tan, grey; Luster: Dull to earthy; Structure: Clastic/Biogenic texture with visible fossil fragments; Cleavage: None (none-foliated)
Formation & geological history
Formed in shallow, warm marine environments where biological debris (shells, coral, microorganisms) accumulated and compacted over millions of years. This specimen likely dates to the Mississippian or Ordovician periods, common in the Kentucky/Ohio River Valley region.
Uses & applications
Used extensively in construction as aggregate, road base, and for architectural stone; also used as a source of lime in agriculture.
Geological facts
The regional coordinates provided (near Louisville, KY) are famous for the Falls of the Ohio, which contain one of the largest exposed Devonian fossil beds in the world, primarily composed of this type of limestone.
Field identification & locations
Identified by its reaction to dilute hydrochloric acid (fizzing) and the presence of visible fossil remains or 'pitted' textures. Commonly found in creek beds and road cuts across the Bluegrass region.
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