Orange Calcite
Calcite var. Orange Calcite · Mineral Specimen and Decorative Stone
Crystal System
Trigonal system; typically exhibits rhombohedral cleavage and massive, scalenohedral, or blocky crystal habits
Mineral Group
Carbonates (specifically an anhydrous carbonate)
Chemical Formula
CaCO3 (Calcium Carbonate with trace iron or organic compounds causing the orange color)
Formation Process
Primarily sedimentary (chemical precipitation in marine environments) or hydrothermal (veins and hot spring deposits). Forms through the precipitation of calcium carbonate from aqueous solutions under varying temperature and pressure conditions.
About This Crystal
The specimen is a chunky, irregularly shaped rough mineral chunk of translucent to semi-translucent orange calcite. It displays a warm honey-orange to golden-yellow body color with lighter white internal banding and cloudy veining. The surface exhibits a vitreous to resinous luster with smooth, undulating cleavage planes characteristic of calcite's perfect rhombohedral cleavage.
Physical Characteristics
Color ranges from bright orange to pale yellow with white zones; white streak; perfect rhombohedral cleavage in three directions intersecting at approximately 75 and 105 degrees; conchoidal to uneven fracture; specific gravity of approximately 2.71; brittle tenacity; displays strong effervescence (fizzing) when exposed to dilute hydrochloric acid; often exhibits pink, orange, or white fluorescence under shortwave and longwave ultraviolet light.
Optical Properties
Uniaxial negative optical sign; very high birefringence (double refraction) which causes a clear doubling of images when viewed through transparent pieces; refractive index ranges from nω = 1.658 to 1.660 and nε = 1.486; vitreous to sub-resinous luster.
Hardness & Durability
Origin Region
Found globally with notable commercial deposits in Mexico, Madagascar, Brazil, and the United States. Forms in sedimentary, metamorphic, and hydrothermal environments.
Hardness & Durability
Mohs hardness of 3, making it very soft and easily scratched by a copper penny or knife. Has poor durability for jewelry due to low hardness and perfect cleavage, which makes it vulnerable to breaking along cleavage planes if impacted.
Care & Maintenance
Requires gentle care due to its low hardness (Mohs 3) and high chemical sensitivity. Clean with a soft, damp cloth and mild soap; avoid harsh chemicals, acids (even mild ones like lemon juice or vinegar which will dissolve the surface), ultrasonic cleaners, and steam. Store separately from harder minerals to prevent scratching.
Rarity & Value
Common; very widely available and affordable as raw chunks, tumbled stones, and carved items. Value depends primarily on size, color saturation, and clarity, typically ranging from low to moderate for mineral specimens.
Special Characteristics
Strong birefringence (double refraction), pronounced effervescence in acid, and distinct fluorescence under ultraviolet light. Often displays internal rhombohedral cleavage planes and subtle color zoning.
Lore & History
While not possessing significant ancient historical lore compared to precious gemstones, calcite has long been utilized in modern crystal healing practices. Orange calcite is traditionally associated with the Sacral Chakra, believed to enhance creativity, vitality, emotional balance, and personal motivation. These are traditional belief systems and cultural symbolisms rather than scientifically validated properties.