Celestite
Celestine · Mineral Specimen
Crystal System
Orthorhombic; typically forms tabular to prismatic crystals, often as rounded nodules or geode fillings with a cluster habit.
Mineral Group
Sulfates
Chemical Formula
SrSO4
Formation Process
Hydrothermal and sedimentary processes, primarily forming as an evaporite mineral in sedimentary basins or via low-temperature hydrothermal precipitation in cavities and veins.
About This Crystal
The specimen is a cluster of pale sky-blue crystals with translucent to transparent clarity and a vitreous to pearly luster. The crystals exhibit a radial or clustered habit showing well-defined faces and terminations typical of celestite geodes.
Physical Characteristics
Pale sky-blue body color with a white streak. Perfect cleavage on {001}, distinct on {210} and {010}. Fracture is uneven. Specific gravity is approximately 3.97. Tenacity is brittle. May show faint blue or white fluorescence under shortwave UV light.
Optical Properties
Biaxial positive with refractive indices around n_alpha = 1.622, n_beta = 1.624, n_gamma = 1.631. Birefringence is 0.009 (low). Pleochroism is weak to absent.
Hardness & Durability
Origin Region
Madagascar, United Kingdom, USA, Mexico, and Poland; commonly found in sedimentary rocks, evaporite deposits, and vugs in limestone or basalt.
Hardness & Durability
Mohs hardness of 3 to 3.5. Very poor durability for jewelry due to perfect cleavage and low hardness, making it easily scratched and broken.
Care & Maintenance
Clean gently with a soft cloth or lukewarm water. Avoid harsh chemicals, ultrasonic cleaners, and steam cleaning. Store away from direct sunlight to prevent color fading and keep separate from harder minerals to avoid scratching.
Rarity & Value
Common to uncommon as a mineral specimen. Value depends on crystal size, color saturation, perfection, and matrix association. Prices range from modest for small clusters to higher values for large, deep blue geode specimens. Treatments are rare.
Special Characteristics
Known for its delicate sky-blue coloration and perfect cleavage. Frequently found filling fossil shells or lining cavities in sedimentary rocks.
Lore & History
Discovered in the late 18th century, named from the Latin 'caelestis' meaning celestial, due to its soft blue sky color. In crystal healing lore, it is traditionally associated with the third eye and crown chakras, believed to promote calm, peace, and spiritual elevation.