fossil

Fossiliferous Limestone

Sedimentary Calcium Carbonate (CaCO3) Matrix with Fossil Fragments

Hardness: 3-4 on Mohs scale; Color: Gray, brownish-gray, and tan with subtle pearlescent highlights; Luster: Dull to earthy matrix, vitreous to pearlescent on shell/fossil inclusions; Cleavage: None (conchoidal to uneven fracture); Specific Gravity: 2.5-2.7

Hardness: 3-4 on Mohs scale

Identified July 26, 2026More fossil →

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Physical properties

Formation & geological history

Formed in shallow, warm marine environments through the accumulation and cementation of organic skeletal debris, shell fragments, bryozoans, and calcite matrix over millions of years (Paleozoic to Cenozoic eras).

Uses & applications

Used extensively in construction as dimension stone, gravel aggregate, manufacturing of cement and lime, soil conditioner in agriculture, and as collector specimens for paleontology enthusiasts.

Geological facts

Fossiliferous limestones preserve ancient marine ecosystems, offering a window into prehistoric seas. Small cavities within these rocks often feature secondary calcite crystals or pyritized fossil impressions.

Field identification & locations

Identified by reacting (fizzing) with dilute hydrochloric acid, presence of fossil molds, casts, or shell debris within a fine-grained carbonate matrix. Found worldwide in ancient marine sedimentary basins, road cuts, and limestone quarries.

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