sedimentary
Fossiliferous Limestone (Coral Rag)
Biogenic Limestone (Calcium Carbonate, CaCO3)
Hardness: 3-4 (Mohs), Color: White to light tan, Luster: Dull/Earthy, Crystal Structure: Orthorhombic (Aragonite) or Trigonal (Calcite), Cleavage: None visible, Specific Gravity: 2.3-2.7
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Physical properties
Hardness: 3-4 (Mohs), Color: White to light tan, Luster: Dull/Earthy, Crystal Structure: Orthorhombic (Aragonite) or Trigonal (Calcite), Cleavage: None visible, Specific Gravity: 2.3-2.7
Formation & geological history
Formed from the accumulation of skeletal fragments of marine organisms such as coral, mollusks, and foraminifera in shallow, warm sea environments. This specimen appears to be of Holocene or Pleistocene origin.
Uses & applications
Used as a building material in tropical coastal regions, in the manufacturing of cement, as a decorative garden stone, and as substrate for marine aquariums.
Geological facts
Limestone is responsible for most of the world's cave systems. When composed primarily of coral fragments, it is often referred to as 'Coral Rag' and is commonly found in ancient uplifted reef systems.
Field identification & locations
Identify by its porous, skeletal texture and characteristic fizzing reaction (effervescence) when exposed to dilute hydrochloric acid. It is commonly found along coastlines and in ancient seabed deposits.
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