sedimentary

Fossiliferous limestone, possibly coral-bearing

Calcitic limestone (mostly CaCO₃; fossil fragments may include ancient colonial coral or shell material)

AI-generated identification · may be incorrect

Light tan, fine- to medium-grained, earthy and dull with visible fossil-like branching/curved textures. Calcite hardness is Mohs 3, with weak cleavage; specific gravity about 2.6–2.7. Effervesces strongly with dilute hydrochloric acid or household vinegar, especially on a freshly scratched surface.

Identified September 7, 2026More sedimentary →

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At a glance

Common name: Fossiliferous limestone, possibly coral-bearing
Scientific name: Calcitic limestone (mostly CaCO₃; fossil fragments may include ancient colonial coral or shell material)
Category: sedimentary
Identified: September 7, 2026
Method: Standard

AI Estimated Value

About $5–$30 as a common hand specimen; $30–$150 if confirmed, attractive, and clearly fossiliferous.

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

Formed from carbonate mud and biological debris deposited in a shallow marine environment, later compacted and cemented. The exact age cannot be determined from the photograph; regional limestones may range from Paleozoic to Cretaceous. The reported southern New Mexico location makes carbonate rock plausible, though a precise formation requires locality data.

Uses & applications

Used for crushed stone, cement, lime, aggregate, and dimension stone; fossiliferous pieces are collected or displayed. Usually low commercial value unless fossils are exceptionally clear or the slab is attractive.

Geological facts

The markings could be fossil structures, but they may also be bedding, weathering, or mineral veins; the image is insufficient for a species-level fossil identification.

Field identification & locations

Look for consistent fossil patterns, bedding, and acid fizz. Commonly found in sedimentary terrains and road cuts around New Mexico. Avoid acid testing if preservation matters; use a tiny inconspicuous spot.