Cathodoluminescence (CL) image of a diamond mined in Guaniamo, Venezuela. The pattern of the luminescence indicates a complex history and gave rise to the name "Picasso's diamond" for its resemblance to the cubist masterpieces of the Spanish painter. Trapped inside this and similar diamonds is the mineral coesite. The oxygen-isotope ratio in the coesite matches that of ocean-floor basalt and suggests that the subduction of oceanic plates was involved in the formation of the early continents. The image represents a diamond 2 mm across. Image courtesy of Prof. Daniel Schulze, Geological Sciences, University of Toronto (published in Nature 2003, v423). This article was published on 2024-07-01
