metamorphic

Weathered limestone or calcitic marble

Calcite-rich carbonate rock, chiefly CaCO₃; likely fossiliferous limestone, possibly weakly metamorphosed marble

AI-generated identification · may be incorrect

Tan to cream, massive and strongly weathered, with irregular cavities and possible fossil textures; calcite has Mohs hardness 3, vitreous to earthy luster, rhombohedral cleavage, and specific gravity about 2.7. It should fizz vigorously with dilute hydrochloric acid or vinegar if exposed fresh.

Identified September 6, 2026More metamorphic →

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Physical properties

Formation & geological history

Likely formed as marine carbonate sediment from accumulated shells or chemical precipitation, later lithified; if marble, heat and pressure recrystallized the calcite. The image alone cannot establish geological age, but carbonate rocks range from Precambrian to recent.

Uses & applications

Used for cement, agricultural lime, aggregate, building stone, and—when attractive or recrystallized—as decorative marble; this weathered specimen has mainly educational or display value.

Geological facts

The pits may represent dissolved fossils, vugs, or weathering along calcite-rich zones. Strong acid effervescence and visible fossil outlines would favor limestone over marble.

Field identification & locations

Common in sedimentary basins and former shallow seas worldwide; identify with acid fizz, low hardness, and light-colored carbonate texture. Approximate value: $5–$30 for a common hand specimen, or $30–$100 if fossil-rich or unusually aesthetic.