Search

Abstract: One of the commercial challenges today in the gem industry is to quickly identify the origin of color in pink diamonds — natural, treated and synthetic by use of standard and advanced gemological instruments. An analytical technique that is used by many gem labs involves UV fluorescence. The principle factors in the technique are the excitation wavelengths and the emission spectra. No systematic study of fluorescence of pink natural diamonds, pink treated and pink synthetic diamonds has been undertaken. This study is mainly focused on using fluorescence techniques to characterize pink diamonds and to compile a reference library of emission spectra. Longwave (LW) and shortwave (SW) fluorescence of 365, 254 and 220 nm illumination were used in a custom built microscope with a fluorescence camera to record images and a spectrometer to record spectral data with which to establish a correlation with the cause of color. Other advanced instruments (CL imaging, UV–VIS–NIR, FTIR, PL spectroscopy and electrical conductance) were used to establish additional criteria for distinguishing natural, treated and synthetic pink diamonds and to find a correlation with the “EGL USA CIS (Cross-reference Identification System) fluorescence method”. [Copyright &y& Elsevier]

Boron ions (2 MeV) were implanted into type IIa natural diamond samples to create deep buried conducting layers. The implantation was carried out at room temperature, followed by furnace annealing at temperatures up to 1650 °C. Data of Hall effect and conductivity measurements are presented in a wide temperature range, which clearly show p-type conduction with an activation of up to 30% of the implanted boron atoms, which is the highest value yet reported for ion implanted diamond. [Copyright &y& Elsevier]