Nephrite Jade
Nephrite (Intermediate member of Tremolite-Actinolite series) · Semi-Precious Gemstone / Decorative Stone
Crystal System
Monoclinic; crystal habit is typically massive or fibrous (felted/interlocking microstructures)
Mineral Group
Silicates; Inosilicate (Double-chain Amphibole group)
Chemical Formula
Ca2(Mg,Fe)5Si8O22(OH)2
Formation Process
Metamorphic; specifically contact or regional metamorphism of magnesium-rich rocks (ultramafic rocks) or dolomitic limestones.
About This Crystal
A polished dark forest green sphere showing a deep, cloudy transparency. The luster is vitreous to waxy, displaying a mottled green color distribution with dark, nearly black inclusions.
Physical Characteristics
Color: Dark Green; Streak: White; Cleavage: None (in massive form); Fracture: Splintery to uneven; Specific Gravity: 2.90–3.03; Tensile strength is exceptionally high due to interlocking fibers; non-fluorescent.
Optical Properties
Refractive Index: 1.600–1.627; Birefringence: 0.027 (often masked in massive aggregate); Lacks pleochroism in aggregate form; Doubly refractive but behaves as AGG (aggregate) under a polariscope.
Hardness & Durability
Origin Region
British Columbia (Canada), New Zealand, China (Hetian), and Russia; typically found in metamorphic environments involving serpentinite.
Hardness & Durability
Mohs Hardness: 6.0–6.5; Toughness: Exceptional (highest of all natural stones due to felted structure); Very stable for daily jewelry wear.
Care & Maintenance
Clean with warm soapy water and a soft cloth. Avoid harsh chemicals and ultrasonic cleaners if the stone is fracture-filled. Store away from harder stones like diamonds.
Rarity & Value
Common to Uncommon; value is driven by color saturation, uniformity, and lack of dark inclusions. Nephrite is generally less expensive than Jadeite.
Special Characteristics
Renowned for its extreme toughness; some specimens may show weak chatoyancy if fibrous, but primarily prized for its spinach-green 'mottled' look.
Lore & History
Historically known as the 'Stone of Heaven' in China; used for over 5,000 years for ritual objects, tools, and jewelry. Associated with the Heart Chakra, longevity, and protection.