Orange Calcite

Physical Properties

Hardness: 3 on Mohs scale; Color: Orange, peach, or honey; Luster: Vitreous to waxy/greasy; Crystal structure: Trigonal/Rhombohedral; Cleavage: Perfect rhombohedral in three directions; Specific gravity: 2.71

Formation & Geological History

Forms through sedimentary precipitation in marine environments, hydrothermal veins, or as a constituent of metamorphic marble and igneous carbonatites. Most commercial orange calcite comes from large deposits formed via chemical precipitation.

Uses & Applications

Used as an ornamental stone, in decorative carvings, as a source of calcium in agriculture, as a flux in metallurgy, and widely in metaphysical jewelry and collecting.

Geological Facts

Calcite is famous for its double refraction (birefringence). If you place a clear crystal over text, the letters appear doubled. Orange calcite specifically gets its color from tiny inclusions of hematite or other iron oxides.

Field Identification & Locations

Identify in the field by its softness (can be scratched by a copper coin) and its vigorous effervescence (bubbling) when a drop of dilute cold hydrochloric acid is applied. It often feels slightly waxy to the touch.

Identified on: 5/6/2026

Mode: Standard