sedimentary
Fossiliferous Limestone
Biogenic Limestone (CaCO3)
Hardness: 3 (Mohs scale); Color: light gray to tan; Luster: dull to earthy; Texture: clastic/biogenic with visible fossil fragments; Cleavage: none (conchoidal fracture).
- Hardness
- 3 (Mohs scale)
- Color
- light gray to tan
- Luster
- dull to earthy
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Physical properties
Hardness: 3 (Mohs scale); Color: light gray to tan; Luster: dull to earthy; Texture: clastic/biogenic with visible fossil fragments; Cleavage: none (conchoidal fracture).
Formation & geological history
Formed in warm, shallow marine environments through the accumulation of shell, coral, algal, and fecal debris. Primarily consists of calcium carbonate precipitated from seawater or extracted by marine organisms.
Uses & applications
Used primarily as construction aggregate, source of lime for agriculture, cement manufacturing, and building stone. Highly weathered or polished pieces are used in decorative landscaping.
Geological facts
This specimen is a water-worn pebble showing 'bioclasts'—fragments of ancient marine life. Limestone covers about 10% of the Earth's total land surface and holds the majority of the world's fossils.
Field identification & locations
Identify in the field by its gray color and the presence of small circular or shell-shaped patterns. It will effervesce (fizz) vigorously when exposed to dilute hydrochloric acid or vinegar.
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