METHOD FOR ASSESSING THE GEMOLOGICAL VALUE OF MAGNESIUM-ALUMINUM SPINEL Russian patent published in 2022 - IPC G01N21/64 G01N21/87 

FIELD: gemology.

SUBSTANCE: invention relates to the field of gemological examination and concerns a method for assessing the gemological value of magnesium-aluminum spinel . The method involves obtaining photoluminescence spectra of a magnesium-aluminum spinel sample in the region of 650-950 nm in the confocal microscopy mode at the boiling point of liquid nitrogen when excited by laser radiation with a wavelength of 488 nm. In addition, the method includes determining the position in the spectrum of the N₄ line and determining the ratio of peak intensities of photoluminescence lines at ~684.7-684.5 nm (R-line), at ~703.9 nm (N₄), at ~686.6 nm (N₁), semi-quantitative determination of the relative chromium content #Cr=Cr/(Cr+Al) in the range up to #Cr<0.2 and identification of magnesium-aluminum spinel with low (δ<0.1), medium (0.1<δ<0.3) and high (δ>0.3) degree of reversal of the structure. Based on these data, the thermal history and gemological value of the sample, the use/non-use of ennobling annealing, accompanied by quenching, are determined.

EFFECT: increase in the information content and simplifying the measurement method.

1 cl, 4 dwg, 4 tbl, 4 ex