SYNTHETIC JEWELRY MANUFACTURING MALACHITE AND METHOD OF PREPARATION THEREOF Russian patent published in 2000 - IPC

FIELD: decorative and applied arts. SUBSTANCE: copper carbonate is dissolved in aqueous solution of ammonium carbonate in excessive molar amount of ammonia by 1.5-1.8 times with respect to molar amount of carbonic acid. The resulting solution is evaporated at 40-95 C at variable rate to form polycrystalline aggregate of synthetic malachite. Synthetic malachite comprises, wt %: Cu₂[CO₃](OH)₂, 99.99-99.5 and impurities 0.01- 0.50. Impurities comprise Fe₂O₃ and Na₂O, density of synthetic malachite is 3.9-4.1 g/cubic cm, Moose hardness is 4.0, microhardness is 216-330 kg/sq.mm, spectral maximum of synthetic malachite, as compared with wear resistance of natural malachite, and polishing ability of synthetic malachite with respect to polishing ability of natural malachite is 105-150%. Synthetic malachite has alternating light green and dark green layers. EFFECT: improved properties of synthetic malachite. 20 cl, 6 ex, 1 tbl