sedimentary
Limestone
Calcium Carbonate (CaCO3)
Hardness: 3-4 (Mohs scale), Color: Grey, white, or tan with a dull/earthy luster. It has a fine-grained texture and will fizz when exposed to dilute hydrochloric acid.
- Color
- Grey, white, or tan with a dull/earthy luster
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Physical properties
Hardness: 3-4 (Mohs scale), Color: Grey, white, or tan with a dull/earthy luster. It has a fine-grained texture and will fizz when exposed to dilute hydrochloric acid.
Formation & geological history
Formed through the accumulation of shell, coral, algal, and fecal debris in marine environments, or by chemical precipitation. Most are millions of years old, dating from various geological eras.
Uses & applications
Primarily used in construction (crushed stone, concrete, cement), as a flux in steel production, in glass manufacturing, and as a soil conditioner in agriculture.
Geological facts
Limestone makes up about 10% of the total volume of all sedimentary rocks on Earth. It is the primary material found in famous caves and karst landscapes.
Field identification & locations
Identify in the field by its grey color and its vigorous reaction to acid. It is commonly found in road gravel, quarries, and coastal outcrops. It often contains micro-fossils.
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