sedimentary
Crushed Limestone Aggregate
Limestone (Calcium Carbonate, CaCO3)
Hardness: 3-4 (Mohs scale), Color: light gray to tan, Luster: dull to earthy, Crystal Structure: Trigonal (as calcite), Cleavage: rhombohedral (not visible in aggregate form)
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Physical properties
Hardness: 3-4 (Mohs scale), Color: light gray to tan, Luster: dull to earthy, Crystal Structure: Trigonal (as calcite), Cleavage: rhombohedral (not visible in aggregate form)
Formation & geological history
Formed through the accumulation and compression of marine organisms like coral, shells, and algae, or by precipitation from water. This specimen appears to be an angular fragment of crushed bedrock.
Uses & applications
Primarily used in construction for road base, concrete aggregate, railroad ballast, and building materials. In powdered form, used as agriculture lime.
Geological facts
Limestone makes up about 10% of the total volume of all sedimentary rocks. It often contains fossils of marine life that lived millions of years ago.
Field identification & locations
Identify by its light gray color, fine-grained texture, and reaction (fizzing) to a dilute acid like vinegar. Very common in regions with ancient seabed deposits.
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