Nuclear microscopic studies of inclusions in natural and synthetic emeralds

Maps recorded by micro-proton-induced x-ray emission (micro-PIXE) were obta ined for different chemical elements for natural and synthetic emeralds. Ei ghty pieces of natural and synthetic stones were examined. The following in clusions and minerals were observed: (1) color zoning/elemental zoning; (2) brine components; (3) calcite/dolomite; (4) chromite/magnetite; (5) pyrite and the accompanying sphalerite/wurtzite; (6) mica (biotite, phlogopite an d muscovite); (7) feldspar (orthoclase and anorthite of plagioclase); (8) f lux residues/nutrient residues; and (9) seed crystal. These (a) demonstrate d the power of micro-PIXE in revealing inclusions in emeralds, which was us eful for easy and unambiguous identification, and which made the identifica tion of inclusions in rough stones possible; (b) provided some criteria for discrimination between natural and synthetic emeralds; and (c) gave the so urce of some chemical elements, so that their presence derived from the PIX E spectra would be further supported (e,g, Cl in the brine component in nat ural and flux grown emeralds; Cl was previously said to be present only in hydrothermal grown emeralds). Furthermore, the present work showed the powe r of micro-PIXE in the in situ study of minerals. Copyright (C) 2000 John W iley & Sons, Ltd.