sedimentary

Fossiliferous Limestone

Biogenic Limestone (Calcium Carbonate, CaCO3)

AI-generated identification · may be incorrect

Hardness: 3-4 (Mohs); Color: Gray, tan, or buff; Luster: Dull/Earthy; Crystal Structure: Microcrystalline with visible fossil inclusions; Cleavage: None/Irregular; Specific Gravity: 2.3 - 2.7.

Hardness: 3-4 (Mohs)
Color: Gray, tan, or buff
Luster: Dull/Earthy

Identified June 29, 2026More sedimentary →

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Physical properties

Hardness: 3-4 (Mohs); Color: Gray, tan, or buff; Luster: Dull/Earthy; Crystal Structure: Microcrystalline with visible fossil inclusions; Cleavage: None/Irregular; Specific Gravity: 2.3 - 2.7.

Formation & geological history

Formed in shallow, warm marine environments where biological debris like shells and skeletal remains accumulate. Over millions of years, compaction and cementation by calcium carbonate create the rock.

Uses & applications

Used in construction as a building material, road base, or cement ingredient. In agriculture, it is crushed for soil treatment. Collector value depends on fossil preservation.

Geological facts

Limestone covers about 10% of the Earth's total land surface. It often contains fossils of crinoids, brachiopods, or corals, providing a window into prehistoric marine life.

Field identification & locations

Identify by applying a drop of vinegar or diluted hydrochloric acid; it will fizz (effervesce). Look for visible shell fragments or organic patterns on weathered surfaces. Commonly found in areas that were once ancient inland seas.