TITLE:
Discussing the Coloration Mechanism of Luodian Jade from Guizhou
AUTHORS:
Lei Wang, Jinhui Lin, Taiping Ye, Jing Tan, Bing Wang, Lin Yang
KEYWORDS:
Guizhou, Luodian Jade, Absorption Spectra, Coloration Mechanism
JOURNAL NAME:
Open Access Library Journal,
Vol.7 No.5,
May
20,
2020
ABSTRACT:
In this paper, we have discussed the coloration mechanism based on visible absorption spectra testing by selecting three typical samples of Luodian jade with white, pallor and cyan. The attribution analysis of absorption spectra showed that absorption of Luodian jade in visible light mainly includes charge transfer spectrum of Fe2+ → Ti4+ (at 490 nm - 500 nm) and Fe2+ → Fe3+ (at 523 nm - 536 nm, 646 nm - 657 nm), electron transition 6A1 → 4T2 (4G) of Fe3+ (at 615 nm - 632 nm, 685 nm - 694 nm) and 4T1 (4G) → 6A1 (6S) of Mn2+ electron transition (at 549 nm - 560 nm). The color of Luodian Jade is the mixed color of complementary color caused by light-absorbing at these frequencies; moreover, different frequency absorption intensity determines the purity and brightness of color. At the same time, The results also confirmed that iron ions play an important role in the coloring mechanism especially with cyan color samples.