Synthetic Gem and Allied Crystal Manufacture

alloy alumina aluminum amount apparatus atmospheres atoms autoclave axis barium titanate beryl boron boule calcium titanate carbide carbon carbonaceous material catalyst catalyst metal chromium color compound containing cooling medium corundum crucible cubic diamond cylinder density deposition described desired diameter diamond crystals diamond growth diamond seed crystals discharge discs electrical electrodes employed example feed material Figure flame flux furnace fused garnet gemstone graphite growing grown heater heating high pressure high temperature hydrogen inch iron kilobars lead oxide liner lower melting point method mixture molten nickel niobium non-diamond obtained oxygen particles piston plate portion powder preferred pressure and temperature produced pyrophyllite quartz range reaction chamber reaction vessel refractive refractive index region ring rutile sapphire seed crystal seed diamond shock wave single crystal solution solvent stone strontium titanate substantially suitable surface synthetic tantalum temperature and pressure thickness TiO₂ titanium tube U.S. Patent yttrium-iron garnet