sedimentary

Fossiliferous Limestone (Red Marble)

Bioclastic Limestone (CaCO3)

Hardness: 3 on Mohs scale; Color: Reddish-brown with white inclusions; Luster: Dull to vitreous (polished); Crystal structure: Trigonal (calcite); Cleavage: Perfect rhombohedral in calcite crystals; Specific Gravity: 2.5–2.7

Hardness: 3 on Mohs scale
Color: Reddish-brown with white inclusions
Luster: Dull to vitreous (polished)

Identified May 21, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed in shallow marine environments through the accumulation of shell, coral, and algal debris. The red color is typically due to iron oxide (hematite) impurities. Often dates from the Paleozoic or Mesozoic eras.

Uses & applications

Extensively used as a dimension stone for countertops, fireplace surrounds, flooring, and decorative wall cladding. Also used as a source of lime in industry.

Geological facts

While commonly called 'marble' in the stone trade due to its ability to take a high polish, geologically it is a sedimentary limestone because it contains visible fossils and has not undergone complete metamorphism.

Field identification & locations

Identified by the presence of small visible fossils (allochems) and its reaction (effervescence) to dilute hydrochloric acid. Commonly found in regions with ancient seabed deposits such as Morocco, Italy, and the Central United States.

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