YELLOW STONES
By Aamir Mannan.
YELLOW ORTHOCLASE
Yellow orthoclase from Malagasy makes quite an attractive gem.Its colour is due to ferric iron replacing some of the alumina in the feldspar, and this gives rise to rather vague bands in the blue and violet, wavelength 4480 and 4200 A, the latter being the stronger.
YELLOW SPODUMENE
Yellow spodumene also owes its colour to ferric iron. Its shows two quite narrow bands in the violet at 4380 and 4325 a, which are almost exactly similar to those seen in the jadeite, which has a closely analogous formula. The 4380 band is considerably stronger than its companion.
By Aamir Mannan.
Yellow orthoclase from Malagasy makes quite an attractive gem.Its colour is due to ferric iron replacing some of the alumina in the feldspar, and this gives rise to rather vague bands in the blue and violet, wavelength 4480 and 4200 A, the latter being the stronger.
Yellow spodumene also owes its colour to ferric iron. Its shows two quite narrow bands in the violet at 4380 and 4325 a, which are almost exactly similar to those seen in the jadeite, which has a closely analogous formula. The 4380 band is considerably stronger than its companion.
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