Blue Celestine (in Matrix)
Celestine (IMA-approved: Celestite) · Mineral Specimen / Semi-Precious Gemstone
Crystal System
Orthorhombic; typically occurs in tabular or prismatic habits, or as massive, fibrous, and granular aggregates.
Mineral Group
Sulfates; Barite group.
Chemical Formula
SrSO4 (Strontium Sulfate)
Formation Process
Primarily sedimentary, forming through the precipitation of strontium-rich hydrothermal fluids in cavities (geodes) or as a replacement mineral in evaporite deposits.
About This Crystal
Exhibits a pale sky-blue to white color with a vitreous to pearly luster. This specimen appears as a granular or druzy crystalline mass embedded within a dark, fine-grained host rock (likely basalt or limestone matrix).
Physical Characteristics
Color: pale blue/white; Streak: white; Cleavage: perfect in three directions; Fracture: conchoidal to uneven; Specific Gravity: 3.9–4.0; Fluorescence: occasionally weak yellow-white under UV.
Optical Properties
Refractive Index: 1.622–1.632; Birefringence: 0.009 (Low); Optically Biaxial (+); Weak pleochroism in deeply colored specimens.
Hardness & Durability
Origin Region
Sourced globally with notable deposits in Madagascar (Sakoany mine), Sicily, and Lake Erie region (USA/Canada). Often found in sedimentary rocks like limestone or sandstone.
Hardness & Durability
Mohs hardness: 3 to 3.5. Very brittle with high cleavage sensitivity, making it fragile and generally unsuitable for faceted jewelry except for collectors.
Care & Maintenance
Extremely sensitive! Avoid ultrasonic cleaners, steam, and acids. Clean only with warm soapy water. Store away from direct sunlight as the blue color can fade (photochromic sensitivity).
Rarity & Value
Relatively common in mineral markets, though high-quality large blue geodes are prized. Value is determined by color intensity and crystal clarity. Treatments are uncommon but some material may be irradiated.
Special Characteristics
Known for its distinct high specific gravity for a non-metallic mineral and its characteristic strontium flame test (burns crimson red).
Lore & History
Historically named from the Latin 'caelestis' meaning celestial or heavenly. In metaphysical lore, it is associated with the throat chakra, inner peace, and communication with higher realms. Note: these are traditional spiritual beliefs.