METHOD OF CITRINE PRODUCTION Russian patent published in 1999 - IPC

FIELD: hydrothermal methods of production of single crystals of citrine with different hues used as semiprecious stones in jewelry. SUBSTANCE: citrine is produced under hydrothermal conditions from aqueous solution of potassium carbonate in presence of ions of iron and lithium nitrate with addition of cobalt oxide containing trivalent cobalt at temperature of 300-350 C and pressure of 400-1500 atm on oriented seeds. In so doing, introduced into solution additionally is manganese nitrate (Mn(NO₃)₂•6H₂O) in amount of 0.7- 1.2 g/l. As a result, high-quality quartz facing raw material is produced with color density of more than 1.0 cm^-1, with reddish hue of MADERA grade similar to natural citrine. EFFECT: higher efficiency. 1 tbl