A Rare Yellow Diamond: Reconstruction of the Possible Geological History

In this study, a rare 3.49-carat yellow diamond was analyzed to reconstruct the geological processes that led to its distinctive form. The diamond exhibits growth and dissolution features, indicating a complex history. To preserve the sample’s integrity, non-destructive analytical techniques—including VIS, UV–Vis–NIR, and IR spectroscopy—were employed. The yellow coloration of the diamond is attributed to the presence of N3 and N2 defects. Additionally, other defects such as N3VH0 centers and platelets were detected; however, the latter do not contribute to the coloration. The observations of the etch pits and surface microreliefs suggest that the diamond underwent size reduction due to dissolution events, which also altered its crystal habit over time. The diamond’s initial mixed-habit morphology evolved into a more complex one through a series of growth and dissolution processes that began during mantle storage. Furthermore, the presence of brown surface stains indicates radiation damage, likely acquired during its residence in alluvial deposits at the Earth’s surface.