Orange Calcite

Physical Properties

Hardness: 3 on Mohs scale; Color: Orange to peach; Luster: Vitreous to waxy; Crystal structure: Trigonal/Rhombohedral; Cleavage: Perfect rhombohedral; Specific Gravity: 2.71

Formation & Geological History

Formed through chemical precipitation in sedimentary environments, often in marine settings or around hot springs, where calcium-rich waters evaporate or undergo changes in pressure/temperature.

Uses & Applications

Mostly used for decorative purposes, lapidary work (cabochons and carvings), and as a popular metaphysical or collector mineral. Industrial calcite is used in cement and fertilizer.

Geological Facts

Orange calcite is known for its 'acid-test' reaction; it will effervesce (fizz) if a drop of weak hydrochloric acid or vinegar is applied. It gets its orange color from inclusions of iron oxide or hematite.

Field Identification & Locations

Identify by its waxy feel, softness (can be scratched by a copper penny but not a fingernail), and the characteristic rhombohedral cleavage planes. Commonly found in Mexico, Brazil, and the USA.

Identified on: 4/27/2026

Mode: Standard