sedimentary

Fossiliferous Limestone

Limestone (CaCO3 with Limonite/Goethite staining)

AI-generated identification · may be incorrect

Hardness: 3-4 on Mohs scale. Color: Yellowish-brown to orange-brown due to iron oxide staining, with patches of green algae. Luster: Earthy, dull. Crystal Structure: Trigonal/Microcrystalline calcite matrix containing fossil fragments.…

Hardness: 3-4 on Mohs scale
Luster: Earthy, dull

Identified July 24, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed in shallow, warm, marine environments through the accumulation of organic debris such as shell fragments, corals, and algae mixed with calcium carbonate precipitate. The yellowish-orange coloration comes from secondary weathering and iron oxide (limonite) hydration.

Uses & applications

Used extensively in construction as aggregate, dimension stone, production of lime and cement, soil conditioning in agriculture, and as a popular rock specimen for amateur palaeontology collectors.

Geological facts

Yellowish-brown iron staining often indicates that the rock was exposed to oxygenated, moisture-rich weathering conditions near the Earth's surface for a prolonged period.

Field identification & locations

Identified by its warm brownish-yellow surface staining, rough earthy texture, reaction (effervescence) with dilute hydrochloric acid, and occasional presence of fossil fragments. Extremely common worldwide in sedimentary rock beds.