mineral

Polished white calcite (likely satin spar variety)

Calcite, calcium carbonate (CaCO₃)

AI-generated identification · may be incorrect

Hardness 3 Mohs; white to translucent, pearly-to-glassy luster, and prominent rhombohedral cleavage. The silky banding suggests fibrous satin spar, though the rounded heart shape is human-carved and polished.

Identified August 20, 2026More mineral →

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Physical properties

Formation & geological history

Calcite forms in sedimentary limestones, hydrothermal veins, caves, and metamorphic marbles; it occurs from ancient to modern geological ages. Fibrous varieties crystallize as elongated intergrowths during mineral precipitation.

Uses & applications

Used for decorative carvings, mineral collections, cement, lime, agricultural soil treatment, and optical calcite applications. This heart-shaped specimen has modest ornamental value.

Geological facts

Calcite effervesces vigorously with dilute hydrochloric acid or strong vinegar, especially when scratched or powdered. It is commonly confused with gypsum satin spar, which is softer (hardness 2) and does not effervesce.

Field identification & locations

Look for very soft scratchability, rhombohedral cleavage, and acid fizz; a steel nail should scratch it. Common sources include Mexico, Brazil, Iceland, the United States, and China.