First synthesis of olivine single crystal as large as 250 carats

Comprehensive and conclusive understanding of the anisotropic upper mantle relies on physical property measurements on high-quality homogeneous specimens of various crystallographic directions. Such specimens are ultimately prepared from one large single crystal. A large olivine single crystal (250carats) was synthesized for use in property measurements and laboratory experiments including anisotropic studies. We show a new simple and practical method for producing a large single crystal by using the Czochralski-pulling facilities. The quality of the synthetic olivine single crystal was carefully examined by EPMA and X-ray diffractometer, showing a uniform composition and sharp spots of the olivine lattice, respectively. Our new attempts to use natural olivine with a wide iridium crucible are successful, and promising to produce large olivine single crystals successively.