mineral

White calcite fragment (likely limestone or marble)

Calcite, calcium carbonate (CaCO₃); exact host rock is uncertain from the image

AI-generated identification · may be incorrect

White, opaque, dull-to-vitreous surface with a fine crystalline texture and irregular fracture; calcite has Mohs hardness 3, rhombohedral cleavage, and specific gravity about 2.71. It should effervesce strongly with dilute hydrochloric acid or vinegar, though vinegar may react slowly.

Identified September 9, 2026More mineral →

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At a glance

Common name: White calcite fragment (likely limestone or marble)
Scientific name: Calcite, calcium carbonate (CaCO₃); exact host rock is uncertain from the image
Category: mineral
Identified: September 9, 2026
Method: Standard

AI Estimated Value

Typically under $1 for a small unidentified fragment; approximately $2–$20 if part of an attractive labeled calcite or marble specimen.

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

Calcite precipitates from seawater, groundwater, caves, and hydrothermal fluids, or forms by recrystallization of limestone into marble. The specimen’s geological age and original environment cannot be determined visually.

Uses & applications

Used in cement, lime, aggregate, soil treatment, glass, and chemical manufacturing; clear crystals are collectible, while white fragments generally have little ornamental value.

Geological facts

Calcite is one of the most abundant carbonate minerals and commonly shows double refraction in clear crystals. Its powder is widely used as a filler in paint, plastics, paper, and toothpaste.

Field identification & locations

Identify it by its softness, rhombohedral cleavage, and acid reaction; a steel knife can scratch it, while quartz cannot. Common sources include limestone districts, marble quarries, caves, and hydrothermal veins worldwide.