Gypsum var. Selenite (Fiber)
Gypsum var. Selenite · Mineral Specimen and Decorative Stone
Crystal System
Monoclinic system, typically forming fibrous, tabular, or prismatic crystals and parallel aggregate formations.
Mineral Group
Sulfates (specifically hydrated calcium sulfate)
Chemical Formula
CaSO4·2H2O
Formation Process
Sedimentary/Evaporite formation process, precipitating from high-salinity bodies of water or hot springs under low to moderate temperatures.
About This Crystal
The specimen displays a fine, fibrous crystal strand hanging delicately from a larger, earthy, matte matrix. The fiber is translucent to transparent with a silky, pearly luster, typical of fibrous gypsum varieties.
Physical Characteristics
Color is clear to white, streak is white, perfect cleavage in one direction yielding thin flexible sheets or fibers, conchoidal to uneven fracture, specific gravity of approximately 2.30, very soft and brittle, non-magnetic, and can show fluorescence under UV light.
Optical Properties
Doubly refractive with a low refractive index around 1.52 to 1.53, exhibits moderate birefringence, and often displays silky chatoyancy along fibrous aggregates.
Hardness & Durability
Origin Region
Found globally with major deposits in Mexico, Morocco, USA (Utah and New Mexico), and Poland. Forms in evaporite sedimentary environments.
Hardness & Durability
Mohs hardness of 2, making it extremely soft and easily scratched by a fingernail. Poor durability for jewelry use due to softness, perfect cleavage, and high solubility in water.
Care & Maintenance
Must be kept completely dry as it is water-soluble; clean gently with a soft dry cloth, avoid soaking in water, keep away from harsh chemicals, and store carefully away from harder minerals to prevent scratching.
Rarity & Value
Common mineral worldwide; value is generally low to moderate depending on crystal formation size, clarity, and aesthetic appeal. Enhancements are rarely needed.
Special Characteristics
Notable for its fibrous habit displaying a silky chatoyant sheen and extremely low hardness on the Mohs scale, along with being water-soluble.
Lore & History
Historically named after the Greek word for moon ('selene') due to its moon-like glow. In modern metaphysical practices, it is traditionally associated with clearing negative energy, charging other crystals, and aligning the crown chakra, though these are cultural beliefs rather than scientifically verified claims.