By Aamir Mannan. JADEITE
Fine green jadeite owes its colour almost entirely to chromium, and typical chromium lines are seen in the red. There might be confusion here with
translucent emerald, but in jadeite the lines
are noticeably more diffuse. The douplet (not properly resolved) is centered at 69I5A,and two weaker lines at 6550
and 6300A.There is strong general absorption of the violet end of the spectrum,but if the slit of the spectroscope be opened to allow more light
through,a powerful band at 4370A can be detected lurking in the gloom.this is an iron band,and is seen at its best in the paler varieties of jadeite(white,lavender,pale green).It is narrow
and well-defined,and can be seen in light reflected from the specimen:it thus form a useful test for jade beads and ornaments.A similar but far weaker band may be detected at 4320A.
If the green colour is due to staining, a absorption band in the red due to the dyestuff will reveal the fraud.
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