Encapsulating Earth's deep water filter: Small inclusions in diamonds brought up from the mantle provide valuable clues to the mineralogy and chemistry of parts of Earth that we cannot otherwise sample. Tschauner et al. found inclusions of the high-pressure form of water called ice-VII in diamonds sourced from between 410 and 660 km depth, the part of the mantle known as the transition zone. The transition zone is a region where the stable minerals have high water storage capacity. The inclusions suggest that local aqueous pockets form at the transition zone boundary owing to the release of chemically bound water as rock cycles in and out of this region. Science , this issue p. 1136

Fluorescence and phosphorescence are listed as mineral optical–physical properties in classical gemology textbooks. The trace elements which exist in gems, certain defects in the crystal lattice, and some luminous molecules contribute to luminescence phenomena in gem materials, including fluorescence and phosphorescence. A systematic luminescence study using an excitation-emission matrix (EEM) not only provides detailed information about the emission and excitation peaks, but also indicates the presence of specific trace elements, lattice defects, or luminous substances in gem materials. This provides reliable evidence for the characterization of gems. In this review paper, we briefly summarize luminescence spectroscopy and illustrate its applications in gem materials in our laboratory, including diamonds, fluorite, jadeite jade, hauyne, and amber. Meanwhile, this project is in process and needs more samples from reliable sources to confirm the described data.

Presents a combination of observational and spectroscopic means to separate the three main geographic localities for blue amber, which shows very strong blue fluorescence under sunlight or D65 illumination.

The evolution of defects in diamond under neutron irradiation was studied via molecular dynamics simulation, with under temperatures of 300–1600 K, primary knock-on atom (PKA) energies of 1–5 keV, and incident orientations in [111], [110], and [100]. The results reveal that the formation of Frenkel pairs is insensitive to temperature but strongly dependent on PKA energy and direction. While interstitials are difficult to cluster in diamond, the size and number of vacancy clusters correlate positively with the PKA energy. Moreover, a decrease in thermal spikes is observed, which is ascribed to the fact that most interstitials can bond with surrounding carbon atoms, which prevents them from moving back to the vacancy in the [111] and [100] directions. Consequently, thermal spikes decrease or disappear as the energy increases. This trend shows directional differences. The radiation resistance of diamond with respect to the direction is [110] > [111] > [100] below 1000 K, and [110] > [111] ≈ [100] at temperatures higher (1600 K). This research can be applied in radiation damage prediction and the radiation-related defect interpretation of diamonds.