mineral

Orange Calcite

Calcium Carbonate (CaCO3)

Hardness: 3 on Mohs scale (can be scratched by a copper coin or knife). Color: Pale yellow to deep orange/reddish-brown. Luster: Vitreous to waxy. Crystal Structure: Trigonal/Rhombohedral. Cleavage: Perfect rhombohedral in three directions. Specific Gravity: 2.71.

Hardness: 3 on Mohs scale (can be scratched by a copper coin or knife)
Color: Pale yellow to deep orange/reddish-brown
Luster: Vitreous to waxy

Identified March 25, 2026More mineral →

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Physical properties

Formation & geological history

Formed through sedimentary processes such as the accumulation of shell, coral, and algal debris, or through chemical precipitation in hot springs or limestone caverns. It can be found in deposits dating back to the Paleozoic era and is common in marine environments.

Uses & applications

Predominantly used as a decorative stone, in lapidary work for carvings and cabochons, and as a popular specimen for metaphysical and mineral collectors. In industrial form, calcite is used in lime production, cement, and as a soil neutralizer.

Geological facts

Orange calcite is often called the 'stone of creativity.' It reacts vigorously with dilute hydrochloric acid, producing carbon dioxide bubbles—a classic 'acid test' for carbonates. Some specimens exhibit strong fluorescence under UV light.

Field identification & locations

Identify in the field by its rhombohedral cleavage (blocks look like tilted cubes) and its relative softness compared to quartz. It is commonly found in Mexico, Brazil, and the USA (Utah). Collectors should look for waxy translucency and vibrant orange banding.