China University of Geosciences 1 article published in JoVE Chemistry An Externally-Heated Diamond Anvil Cell for Synthesis and Single-Crystal Elasticity Determination of Ice-VII at High Pressure-Temperature Conditions Xiaojing Lai1,2, Feng Zhu2, Jin S. Zhang3, Dongzhou Zhang2,4, Sergey Tkachev4, Vitali B. Prakapenka4, Bin Chen2 1Gemmological Institute, China University of Geosciences (Wuhan), 2Hawai'i Institute of Geophysics and Planetology, University of Hawai'i at Mānoa, 3Department of Earth and Planetary Sciences, University of New Mexico, 4Center for Advanced Radiation Sources, University of Chicago This work focuses on the standard protocol for preparing the externally-heated diamond anvil cell (EHDAC) for generating high-pressure and high-temperature (HPHT) conditions. The EHDAC is employed to investigate materials in Earth and planetary interiors under extreme conditions, which can be also used in solid state physics and chemistry studies.