sedimentary
Fossiliferous Limestone
Biogenic Limestone with Brachiopod/Crinoid fragments
Hardness: 3-4 (Mohs); Color: Dark gray to brownish matte groundmass with lighter gray fossil inclusions; Luster: Dull/Earthy; Structure: Fine-grained matrix with calcified fossil fragments.
- Hardness
- 3-4 (Mohs)
- Luster
- Dull/Earthy
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Physical properties
Hardness: 3-4 (Mohs); Color: Dark gray to brownish matte groundmass with lighter gray fossil inclusions; Luster: Dull/Earthy; Structure: Fine-grained matrix with calcified fossil fragments.
Formation & geological history
Formed in shallow marine environments where organic debris accumulated over millions of years, typically during the Paleozoic era. The pressure of overlying sediment compacted these remains into rock.
Uses & applications
Used in construction, lime production, and as an ornamental stone in landscaping. Smooth beach-worn specimens are common for amateur collecting and aquarium decor.
Geological facts
The circular and oval light patterns are cross-sections of ancient marine life. Limestone covers about 10% of the Earth's total land surface.
Field identification & locations
Can be identified in the field by its dark, fine-grained matrix containing lighter fossil shells. It will typically react (fizz) when exposed to a weak acid like vinegar due to its calcium carbonate content.
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