Blue Calcite
Calcite · Mineral Specimen and Decorative Stone
Crystal System
Trigonal, massive habit with rhombohedral cleavage forms visible in the internal cavity
Mineral Group
Carbonates
Chemical Formula
CaCO3
Formation Process
Hydrothermal and sedimentary precipitation, forming in veins, cavities, and limestone deposits under low to moderate temperatures and pressures
About This Crystal
A bulbous, egg-shaped or polished nodule that has been cut or broken open to reveal a hollow vug lined with large, pale ice-blue to grey-blue translucent rhombohedral crystals with a vitreous to waxy luster
Physical Characteristics
Light blue body color, white streak, perfect rhombohedral cleavage in three directions at roughly 75 and 105 degrees, uneven to conchoidal fracture, specific gravity around 2.71, brittle tenacity, and often exhibits strong pink to blue-white fluorescence under UV light
Optical Properties
Uniaxial negative with strong birefringence, exhibiting high double refraction which causes a noticeable doubling of images viewed through transparent sections
Hardness & Durability
Origin Region
Commonly sourced from Madagascar, Mexico, and the USA; forms in sedimentary, metamorphic, and hydrothermal environments
Hardness & Durability
Mohs hardness of 3, making it very soft and easily scratched by a copper coin or knife; has poor durability for everyday jewelry due to perfect cleavage and low hardness
Care & Maintenance
Clean with a soft, damp cloth only; avoid soaking in water for extended periods due to slight solubility, avoid all harsh acids (reacts with effervescence), and keep away from prolonged direct sunlight to prevent color fading
Rarity & Value
Common mineral, though aesthetic blue calcite nodules and geode-like formations are moderately priced depending on size and clarity
Special Characteristics
Strong birefringence and pronounced cleavage planes; often exhibits strong fluorescence under ultraviolet light
Lore & History
Popularly used in crystal healing practices as a stone of tranquility, emotional balance, and soothing the third eye and throat chakras, though these are traditional and alternative beliefs without scientific backing