sedimentary

Fossiliferous Limestone

Biogenic Sedimentary Rock (CaCO3)

Hardness of 3 on the Mohs scale, grayish-white color, dull luster, and effervesces when exposed to dilute hydrochloric acid.

Identified November 3, 2026More sedimentary →

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Physical properties

Hardness of 3 on the Mohs scale, grayish-white color, dull luster, and effervesces when exposed to dilute hydrochloric acid.

Formed through the accumulation and compaction of organic carbonate debris and shell fragments in shallow marine environments over millions of years.

Used primarily in the construction industry as crushed stone for road base, aggregate in concrete, and for producing lime and cement.

This specimen contains a visible fossil impression, which is common in limestones formed from ancient marine ecosystems.

Identify in the field by its reaction to acid and visible fossil fragments; commonly found in sedimentary basins worldwide.

Fossil-bearing concretion, possibly containing a fossil shell or other organic inclusion

Calcareous concretion; exact fossil and host-rock composition are not identifiable from the image

Fossiliferous Sedimentary Rock

Sedimentary limestone with invertebrate fossil imprint

Sandstone or Siltstone

Arenite (if sandstone)

Sandstone

Arenite

Shale

Shale (clastic sedimentary rock)

Shale (or Mudstone/Siltstone)

Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)