sedimentary
Limestone (Pebble)
Calcium Carbonate (CaCO3)
Hardness: 3 (Mohs Scale), Color: Grey to light tan, Luster: Dull/Earthy, Crystal Structure: Trigonal (microcrystalline), Cleavage: None/Conchoidal, Specific Gravity: 2.5-2.7
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Physical properties
Hardness: 3 (Mohs Scale), Color: Grey to light tan, Luster: Dull/Earthy, Crystal Structure: Trigonal (microcrystalline), Cleavage: None/Conchoidal, Specific Gravity: 2.5-2.7
Formation & geological history
Formed through the accumulation of shell, coral, algal, and fecal debris in marine environments. This specimen has been rounded and smoothed by water erosion (aeolian or fluvial processes).
Uses & applications
Primarily used in construction (crushed stone), cement production, as a soil conditioner in agriculture, and for architectural cladding.
Geological facts
Limestone makes up about 10% of the total volume of all sedimentary rocks on Earth. Most limestone is formed in shallow, calm, warm marine waters.
Field identification & locations
Identify in the field by its softness (can be scratched by a copper penny) and its reaction (fizzing) when exposed to a weak acid like vinegar. Commonly found on beaches, riverbeds, and in karst landscapes.
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