sedimentary
Limestone River Pebble
Sedimentary Calcium Carbonate (CaCO3)
Hardness: 3-4 (Mohs scale); Color: Gray to tan; Luster: Dull/Earthy; Structure: Fine-grained/Microcrystalline; Cleavage: None/Irregular; Specific Gravity: 2.5-2.7
- Hardness
- 3-4 (Mohs scale)
- Color
- Gray to tan
- Luster
- Dull/Earthy
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Physical properties
Hardness: 3-4 (Mohs scale); Color: Gray to tan; Luster: Dull/Earthy; Structure: Fine-grained/Microcrystalline; Cleavage: None/Irregular; Specific Gravity: 2.5-2.7
Formation & geological history
Formed by the accumulation of shell, coral, algal, and fecal debris in warm, shallow marine waters, later compressed and smoothed by water erosion in a river or coastal environment.
Uses & applications
Used extensively in the construction industry for cement, road base, and landscape architecture. Common specimens are used as decorative garden stones.
Geological facts
The holes or 'pitting' on the surface are likely caused by water-driven erosion or the presence of trace fossils and softer inclusion weathering out over time.
Field identification & locations
Identified by its reaction to dilute hydrochloric acid (fizzing), its relatively soft surface compared to quartz, and its rounded, water-worn shape. Commonly found in riverbeds and on beaches.
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