sedimentary

Fossiliferous Limestone

Biogenic Limestone (Calcium Carbonate, CaCO3)

AI-generated identification · may be incorrect

Hardness: 3 (Mohs scale); Color: Gray to tan; Luster: Dull/Earthy; Crystal structure: Orthorhombic or Trigonal (microcrystalline matrix); Cleavage: None; Specific gravity: 2.3-2.7

Hardness: 3 (Mohs scale)
Color: Gray to tan
Luster: Dull/Earthy

Identified June 30, 2026More sedimentary →

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Physical properties

Hardness: 3 (Mohs scale); Color: Gray to tan; Luster: Dull/Earthy; Crystal structure: Orthorhombic or Trigonal (microcrystalline matrix); Cleavage: None; Specific gravity: 2.3-2.7

Formation & geological history

Formed in shallow marine environments through the accumulation of shell, coral, and algal debris. This specimen appears to contain crinoid stem fragments or small shells from the Paleozoic era.

Uses & applications

Used in construction as aggregate, in the manufacture of cement, as a decorative stone, and in agriculture to neutralize soil acidity.

Geological facts

Limestone makes up about 10% of the total volume of all sedimentary rocks. It often contains well-preserved fossils that provide a window into ancient ocean life.

Field identification & locations

Identify in the field by its grainy texture and the presence of visible fossils or 'rings'. It will effervesce (fizz) when exposed to a drop of cold dilute hydrochloric acid. Commonly found in former seabed regions.