Satin Spar Selenite
Gypsum var. Satin Spar · Decorative Stone and Mineral Specimen
Crystal System
Monoclinic; typically forms as fibrous aggregates, massive, or elongated prismatic crystals.
Mineral Group
Sulfates; specific subgroup is hydrated calcium sulfate.
Chemical Formula
CaSO4·2H2O
Formation Process
Sedimentary, formed through the evaporation of salt-water lakes and ancient seas (evaporite deposits) under arid conditions.
About This Crystal
The specimen is a smoothly polished, tumbled stone with a translucent to opaque white body color. It exhibits a distinct silky luster and a characteristic glowing band of light (chatoyancy) running across its surface due to its fibrous internal structure.
Physical Characteristics
Color is white to colorless with a white streak. Perfect cleavage in one direction yielding thin, flexible sheets. Fracture is uneven or fibrous. Specific gravity is approximately 2.3. Tenacity is sectile and flexible in thin layers. Exhibits weak white or yellow fluorescence under shortwave UV light.
Optical Properties
Biaxial positive with refractive indices around 1.520 to 1.530. Displays strong chatoyancy (the cat's-eye effect) when cut into cabochons or polished smooth, caused by light reflecting off parallel fibrous inclusions.
Hardness & Durability
Origin Region
Major deposits are found in Mexico, Morocco, Poland, and the United States (such as Utah).
Hardness & Durability
Mohs hardness of 2, making it very soft and easily scratched by a fingernail. Low toughness and poor wearability for everyday jewelry due to extreme softness and perfect cleavage.
Care & Maintenance
Extremely water-soluble; never submerge in water or use liquid cleaners. Clean with a dry microfiber cloth only. Store separately to prevent scratching and keep away from high humidity.
Rarity & Value
Common and widely available. Value is low to moderate, depending on size, polish quality, and chatoyancy strength. Treatments are generally not applied as the natural material is abundant.
Special Characteristics
Exhibits strong chatoyancy (satin spar effect) resembling a glowing thread of light. Highly soluble in water and very soft.
Lore & History
Named after Selene, the Greek goddess of the moon, due to its moon-like pearly glow. In crystal healing lore, it is widely believed to be a powerful cleansing and purifying stone that can clear negative energy and charge other crystals, though these are traditional beliefs rather than scientific claims.