Synthesis of transparent polycrystalline jadeite under high pressure and temperature

Keisuke Mitsu, Tetsuo Irifune, Hiroaki Ohfuji, Akihiro Yamada

Research output: Contribution to journalArticlepeer-review


Attempts to synthesize transparent polycrystalline jadeite have been made by direct conversion from bulk glass at pressures 10–20 GPa and temperatures 900–1300 °C using Kawai–type multianvil apparatus. The grain size of jadeite tends to decrease with increasing pressure, but we failed to synthesize polycrystalline jadeite with grain sizes in nano–regime (<100 nm) and obtained the sample with the smallest average grain size of ~ 240 nm at 20 GPa and 1300 °C for 20 min. Polycrystalline jadeite of the minimum grain size exhibits high optical transparency with a transmittance of ~ 70% for a typical wavelength in the visible region. The highest Vickers hardness (Hv) of 14.2 GPa was observed for the polycrystalline jadeite sample with the minimum grain size of ~240 nm, which is about 7% higher than the hardness (Hv = 13.3 GPa) of the sample with the largest grain size of ~ 390 nm. Further increases in optical transparency and hardness of polycrystalline jadeite would be realized if we get nano–polycrystalline samples by optimizing pressure, temperature, heating duration, etc. of the ultrahigh–pressure synthesis experiment.

Original languageEnglish
Pages (from-to)203-210
Number of pages8
JournalJournal of Mineralogical and Petrological Sciences
Issue number4
Publication statusPublished - 2021


  • Jadeite
  • Nano–polycrystal
  • Transparent ceramics
  • Utrahigh–pressure synthesis

ASJC Scopus subject areas

  • Geophysics
  • Geology


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