sedimentary
Limestone River Pebble
Sedimentary Calcium Carbonate (CaCO3)
Hardness: 3-4 on Mohs scale; Color: Gray to light tan; Luster: Dull/Earthy; Crystal structure: Trigonal (microcrystalline); Specific gravity: 2.5-2.7
- Hardness
- 3-4 on Mohs scale
- Color
- Gray to light tan
- Luster
- Dull/Earthy
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Physical properties
Hardness: 3-4 on Mohs scale; Color: Gray to light tan; Luster: Dull/Earthy; Crystal structure: Trigonal (microcrystalline); Specific gravity: 2.5-2.7
Formation & geological history
Formed from the accumulation of shell, coral, algal, and fecal debris in marine environments, subsequently rounded by water erosion in a river or coastal setting.
Uses & applications
Commonly used as aggregate in construction, landscape decoration, and as a raw material for cement and lime production.
Geological facts
Limestone makes up about 10% of the total volume of all sedimentary rocks. It often contains microscopic fossils or 'bio-clasts' visible under magnification.
Field identification & locations
Identify by its reaction (fizzing) when exposed to a weak acid like vinegar. Commonly found in riverbeds, lake shores, and ancient sea beds. Useful for landscape gardening.
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