sedimentary
Fossiliferous Limestone
Biomicrite / Limestone with fossils
Hardness: 3-4 (Mohs scale); Color: Gray, tan, and dark carbonaceous patches; Luster: Dull to earthy; Crystal structure: Microcrystalline (calcite); Specific Gravity: 2.3–2.7
- Hardness
- 3-4 (Mohs scale)
- Color
- Gray, tan, and dark carbonaceous patches
- Luster
- Dull to earthy
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Physical properties
Hardness: 3-4 (Mohs scale); Color: Gray, tan, and dark carbonaceous patches; Luster: Dull to earthy; Crystal structure: Microcrystalline (calcite); Specific Gravity: 2.3–2.7
Formation & geological history
Formed in shallow, calm marine environments from the accumulation of calcium carbonate and organic remains of marine organisms such as brachiopods, crinoids, and mollusks. Often dates back to Paleozoic or Mesozoic eras.
Uses & applications
Used primarily in the construction industry as crushed stone, road base, or cement. High-quality pieces are used for landscaping or as educational geological specimens.
Geological facts
This specimen contains visible fossil imprints and shells. Limestone makes up about 10% of the total volume of all sedimentary rocks and is a major reservoir for oil and natural gas.
Field identification & locations
Identify in the field by looking for visible shell fragments and testing with diluted hydrochloric acid (it will fizz). Commonly found in areas that were once ancient seabeds.
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