Inclusions and Gemological Characteristics of Emeralds from Kamakanga, Zambia

Abstract

Currently, Zambia is one of the world’s major emerald-producing countries. In this study, emerald samples from Kamakanga, Zambia, were systematically analyzed by standard gemological tests, microscopic observation, Raman spectroscopy test of mineral inclusions, and fluid inclusions. The study found Kamakanga emeralds have higher RI (refractive index) and SG (specific gravity) than average. The common inclusions in Kamakanga emeralds are pseudo-hexagonal, dark green, brownish, or oval platelet phlogopite; red spot or skeletal hematite; black spot, platelet, or dendritic oxide inclusions (pyrolusite, magnetite, ilmenite); or schorl. The common paragenetic mineral is schorl. Other mineral inclusions are fluorapatite, tremolite, and calcite. All Kamakanga emeralds contain at least two kinds of common mineral inclusions that are described above, and the characteristic mineral inclusions are pseudo-hexagonal dark green platelet phlogopite and a large quantity of fluorapatite. The fluorapatite inclusions with colorless transparent rims and greyish hazy interiors are reported for the first time. Most fluid inclusions in Kamakanga emeralds are rectangular two- or three-phase inclusions, containing gas phase (CO2 + CH4 + H2O or CO2), aqueous fluid, and sometimes solid phase (carbonate). A small number of hexagonal three-phase fluid inclusions can be seen in Kamakanga emeralds, containing gas phase (CO2 + CH4), aqueous fluid, and daughter crystals (siderite).