sedimentary

White coral limestone (probable fossiliferous limestone)

Calcite (CaCO₃), commonly derived from aragonitic coral skeletons recrystallized to calcite

AI-generated identification · may be incorrect

Soft to moderately hard (Mohs 3), white to pale gray, dull to weakly pearly luster, fine-grained and porous, with rounded fossil or coral cavities; no obvious cleavage in the specimen. It effervesces strongly in dilute hydrochloric acid or vinegar, though vinegar may react slowly.

Identified August 14, 2026More sedimentary →

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At a glance

Common name: White coral limestone (probable fossiliferous limestone)
Scientific name: Calcite (CaCO₃), commonly derived from aragonitic coral skeletons recrystallized to calcite
Category: sedimentary
Identified: August 14, 2026
Method: Standard

AI Estimated Value

About $2–$20 for a small common specimen; $20–$75 or more for large, clearly identifiable fossil coral with attractive preservation.

Not an official valuation

AI estimate for general interest only — not an appraisal. Actual value depends on condition, provenance, and market demand. Verify with a professional before buying, selling, or insuring.

This identification was generated by AI and may contain errors. Verify important details before relying on them — and never use an AI result to judge whether a specimen is safe to handle. Read the full disclaimer

Physical properties

Formation & geological history

Marine biogenic sediment formed from accumulated coral or shell material, later compacted and lithified; recrystallization can occur during diagenesis. Its age cannot be determined from the image and may range from recent coral-derived deposits to ancient limestone.

Uses & applications

Used as aggregate, cement and lime feedstock, soil amendment, and decorative stone; attractive fossil-rich pieces are collected but are generally not gemstone grade.

Geological facts

The rounded depressions and branching-looking textures are consistent with coral or other marine fossils rather than a crystalline mineral specimen.

Field identification & locations

Common in former reef environments, coastal limestones, and uplifted marine strata worldwide. Confirm with acid fizz, a hardness test, and inspection for corallite walls or fossil structure; avoid confusing it with porous concrete or plaster.