ABSTRACT
ABSTRACT: The origin of the color in natural, type Ha brown diamonds is not known despite extensive study. Here, EELS is used to investigate the density of states associated with dislocations. A dislocation may give rise to localized energy states in the band gap, allowing the absorption of photons with energies in the visible range. EELS spectra taken off dislocations were subtracted from spectra taken on dislocations and the difference compared for a brown, colorless, and brown diamond after annealing. The data indicates the presence of additional energy states for electrons at dislocations in the brown diamond when compared with the colorless and annealed diamond.
