Jade (Nephrite)
Image: <a rel="nofollow" class="external text" href="https://www.flickr.com/people/47445767@N05">James St. John</a> (CC BY 2.0)
Mineral NameJade (Nephrite)
Chemical FormulaCa₂(Mg,Fe)₅Si₈O₂₂(OH)₂
Mohs Hardness6
Crystal Systemmonoclinic
Lustervitreous
Streak Colorwhite
CleavageNone (due to fibrous aggregate structure, though constituent amphiboles have perfect cleavage)
Fracturesplintery
Specific Gravity2.95
Colorsgreen, dark green, light green
Transparencytranslucent
Type LocalitySouth Island, New Zealand (Pounamu Ultramafic Belt)
Mineral GroupSilicates (Amphibole Group)
Usesjewelry, carvings, ornamental objects, tools, collector
Associated Mineralsserpentine, chromite, magnetite, talc
Rarityuncommon
Description
This is a large, irregularly shaped, polished slice of deep green nephrite jade, displaying a mottled and banded texture with lighter green veins and darker inclusions.
Geological Context
Nephrite is a metamorphic rock formed by the alteration of ultramafic rocks (like serpentinites) or dolomitic limestones under conditions of regional metamorphism, often found in subduction zone environments.
