sedimentary

Oolite or Oolitic Limestone

Oolitic Limestone (Principal mineral: Calcite, CaCO3)

AI-generated identification · may be incorrect

Hardness: 3-4 (Mohs scale), Color: Tan, beige, brown, or gray, Luster: Dull to earthy, Structure: Small spherical grains (ooliths) less than 2mm, Cleavage: None (rhombohedral for individual crystals)

Identified February 8, 2026More sedimentary →

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Physical properties

Hardness: 3-4 (Mohs scale), Color: Tan, beige, brown, or gray, Luster: Dull to earthy, Structure: Small spherical grains (ooliths) less than 2mm, Cleavage: None (rhombohedral for individual crystals)

Formation & geological history

Formed in warm, shallow, supersaturated marine waters. Ooliths grow as calcium carbonate precipitates around a sand grain or shell fragment nucleus while being agitated by wave action. Majority are from the Jurassic to Holocene periods.

Uses & applications

Used in construction as a dimension stone, decorative aggregate, lime production, and occasionally as a specimen for educational geology kits.

Geological facts

The word 'oolite' comes from the Greek word 'oion' for egg, describing its resemblance to fish roe. Much of the Florida Everglades and the Bahamian platform are underlain by oolitic limestone formations.

Field identification & locations

Identified by its 'fish roe' texture of tiny spheres. Can be tested with dilute HCl (will fizz). Found in sedimentary basins globally, commonly in areas like the UK (Portland Stone) and the Midwestern USA (Indiana Limestone).