Nephrite Jade
Actinolite-Tremolite var. Nephrite · Semi-Precious Gemstone / Decorative Stone
Crystal System
Monoclinic; commonly occurs in massive, microcrystalline fibrous aggregates with interlocking felted structures.
Mineral Group
Silicates (Inosilicates) - Amphibole Group
Chemical Formula
Ca2(Mg,Fe)5Si8O22(OH)2
Formation Process
Metamorphic; typically forms through the regional or contact metamorphism of serpentinite or dolomitic limestones under high pressure.
About This Crystal
Dense, tough stone with a deep spinach green to sage green color. The specimen is polished (tumbled), showing a greasy or waxy to vitreous luster. It is translucent to opaque with visible dark speckling and lighter green cloudy inclusions.
Physical Characteristics
Color: Forest green; Streak: White; Cleavage: None visible in massive form (though individual fibers have prismatic cleavage); Fracture: Splintery to granular; Specific Gravity: 2.90–3.03; Fluorescence: Typically inert.
Optical Properties
Refractive Index: 1.606–1.632; Birefringence: 0.027 (though often aggregate RI is used); Pleochroism: Weak; Optical Phenomenon: Occasional chatoyancy in rare fibrous specimens.
Hardness & Durability
Origin Region
New Zealand (Pounamu), British Columbia (Canada), Wyoming (USA), Russia, and China (Hotan); forms in metamorphic rocks and alluvial deposits.
Hardness & Durability
Mohs Hardness: 6.0–6.5; Toughness: Exceptional (highest of any natural stone due to interlocking fibers); Stability: Excellent, resistant to breakage.
Care & Maintenance
Safe with warm soapy water and soft brush; avoid ultrasonic cleaners and harsh chemicals. Store separately from harder gemstones like diamonds or sapphires to prevent scratches.
Rarity & Value
Relatively common but high-quality translucent green material is valuable. Treatments are rare for Nephrite (unlike Jadeite), though occasionally waxed or dyed.
Special Characteristics
Renowned for its extreme toughness; characterized by a 'felted' microcrystalline structure that prevents cleavage propagation.
Lore & History
Historically significant in Maori culture (Pounamu) for tools and ornaments, and in ancient China (The Stone of Heaven) symbolizing virtue, longevity, and status. Traditionally associated with the Heart Chakra and believed to promote emotional balance and prosperity.