Relationship between photoluminessence spectra and textures of natural polycrystalline diamonds, carbonados

Abstract

Photoluminescence (PL) spectroscopy and textural analyses were performed for two samples of natural polycrystalline diamonds, carbonados, from the Central African Republic. Theses samples revealed distinctly different PL spectral: sample-A is characterized by 3H center and absence of 575 nm N-V center whereas H3 center and 575 nm N-V center are evident in sample-B. The former and the latter are respectively typical of Group-A and Group-B of Kagi et al. (1994, 2007). Textural characteristics are also different between the two samples: for example, voids of ca. 1-10 microns are pervasively distributed in sample-A whereas voids are large and localized in sample-B. Based on these observations, we will discuss about timing and mechanism of irradiation of carbonados.