sedimentary
Fossiliferous Limestone
Calcium Carbonate (CaCO3) with Biogenic Inclusions
Hardness: 3-4 (Mohs scale); Color: Light gray to tan; Luster: Dull/Earthy; Structure: Fine-grained matrix with fossil imprints or inclusions; Specific Gravity: 2.5-2.7
- Hardness
- 3-4 (Mohs scale)
- Color
- Light gray to tan
- Luster
- Dull/Earthy
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Physical properties
Hardness: 3-4 (Mohs scale); Color: Light gray to tan; Luster: Dull/Earthy; Structure: Fine-grained matrix with fossil imprints or inclusions; Specific Gravity: 2.5-2.7
Formation & geological history
Formed in warm, shallow marine environments from the accumulation of organic debris such as shell, coral, algae, and fecal debris. This specimen appears to contain weathered fossil fragments, potentially dating to the Paleozoic or Mesozoic eras.
Uses & applications
Primarily used in construction as an aggregate, cement production, agriculture for pH control, and as decorative stone or for fossil collecting.
Geological facts
Limestone covers about 10% of the Earth's total land surface. Many ancient Egyptian pyramids, including the Great Pyramid, were originally cased in polished white limestone.
Field identification & locations
Identify in the field by its characteristic gray color and reaction (fizzing) when exposed to a weak acid like vinegar. Look for visible imprints of shells or small circular patterns which are often fragments of crinoids or brachiopods.
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