METHOD OF PREPARING COLORED MONOCRYSTALS (VERSIONS) Russian patent published in 1999 - IPC

FIELD: crystal growing. SUBSTANCE: invention aims at growing synthetic monocrystals that are fit to manufacture jewelry articles. Charge containing, mol %: metal oxide, 18-57; cobalt oxide, 0.28-3.0; neodymium oxide, 0.05-1.0; zirconium and/or hafnium oxide, the balance, is placed in container with cooled walls. Charge is heated to form melt within skull layer. Directed crystallization of melt is conducted by displacing container relative to heating zone. Container is then withdrawn from heating zone and monocrystals are cooled, annealed under inert gas atmosphere or in vacuum at 500 to 1600 C for 0.5-5.0 hr. In another embodiment of invention, charge is composed of, mol %: metal oxide 8.0-480, cobalt oxide 0.1-15.0, praseodymium oxide 2.0-28.9, zirconium and/or hafnium oxide - the balance. To achieve emerald color, monocrystals are annealed under inert gas atmosphere or in vacuum at 600 to 1400 C for 0.5-10.0 hr. EFFECT: achieved close similarity to natural gems. 6 cl, 4 dwg, 2 tbl