English: Jadeitite (lavender jadeitite) (18.2 cm across at its widest) from the Hpakan-Tawmaw Jade Tract (near-latest Jurassic, 147 m.y.) of northern Burma. The light brown-colored rim is a weathering rind. Lavender is a scarce color variation seen in Burmese jadeitites. Whitish and near-white jadeite occurs throughout this rock, as well as hints of pale-greenish gray jadeite near the lower left edge.

Published research on Burmese jade generally indicates that the jadeitite rock masses formed by metasomatism of albitites (= plagioclase feldspar metamorphites) at the periphery of serpentinized mantle peridotite bodies. The mantle peridotite was part of a subducting slab of Mesozoic-aged oceanic lithosphere that was emplaced upward and against southeast Asian continental lithosphere by obduction.

Composition: the lavender color of the jadeite clinopyroxene (Na(Al,Fe)(Si2O6)) in this rock appears to be the result of ferrous iron to ferric iron (Fe+2 → Fe+3) intervalence charge transfer (Rossman, 1974).

Geologic unit: Hpakan-Tawmaw Jade Tract, Hpakan Ultramafic Body, Naga-Adaman Ophiolite.

Metamorphic age: late Tithonian Stage, near-latest Jurassic, 147 m.y.

Locality: alluvial clast (placer jade) from unrecorded locality (possibly in the vicinity of Phakant), upper reaches of the Uyu River (Uru River), western Kachin State, Indo-Burma Range, northern Burma.

Photo from & info. synthesized by James St. John (School of Earth Sciences, Ohio State University at Newark; Newark, Ohio, USA).