mineral

Orange Calcite (Polished Sphere)

Calcium Carbonate (CaCO3)

Hardness: 3 on Mohs scale; Color: Pale orange to deep honey-orange with white inclusions; Luster: Vitreous to waxy; Crystal Structure: Trigonal/Rhombohedral; Cleavage: Perfect rhombohedral in raw form; Specific Gravity: 2.71

Hardness: 3 on Mohs scale
Color: Pale orange to deep honey-orange with white inclusions
Luster: Vitreous to waxy

Identified March 14, 2026More mineral →

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Physical properties

Formation & geological history

Formed through sedimentary processes or as a chemical precipitate in marine environments or hydrothermal veins. This mineral frequently forms in caves as stalactites or in limestone deposits. Geological age varies greatly by deposit, often ranging from 10 to 500 million years.

Uses & applications

Used primarily for decorative objects (spheres, carvings), jewelry (cabochons), and collection. In industrial form, calcite is used in acid neutralization, as a flux in metallurgy, and as a component in cement and fertilizers.

Geological facts

Orange calcite is known for its 'optical' properties in clear varieties (Iceland Spar); however, the orange variety gets its color from tiny inclusions of hematite or other iron oxides. It is highly reactive to cold dilute hydrochloric acid, which will cause it to effervesce (fizz).

Field identification & locations

Identification in the field is confirmed by its relative softness (can be scratched by a copper coin or steel knife) and its reaction to acid. It is commonly found in Mexico, Brazil, and the USA. For collectors, polished spheres show the inner 'shimmer' or chatoyancy of the crystal structure.

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