Green nodules: reflectance
The green line spectrum shows the reflectance of the green material. The double absorption feature at 430-440nm is seen in jadeite and attributed to ferric iron (Fe3+). I have also seen this feature in yellow topaz which, like jadeite, can contain chromium in the form of Cr3+. The comparison transmission spectra are of olivine (peridot; thin pink line) and chromium-containing jadeite (thin blue line).
Stones with type of nodular morphology have been dubbed 'Nebula Stone' and sold as a lapidary product under this trade name. There is an interesting description and some reported identification efforts at: www.rockhounds.com/rockgem/articles/nebula.shtml
I thank Cran Cowan and Radostin Pavlov for helping with this puzzle.
Green nodules: reflectance
The green line spectrum shows the reflectance of the green material. The double absorption feature at 430-440nm is seen in jadeite and attributed to ferric iron (Fe3+). I have also seen this feature in yellow topaz which, like jadeite, can contain chromium in the form of Cr3+. The comparison transmission spectra are of olivine (peridot; thin pink line) and chromium-containing jadeite (thin blue line).
Stones with type of nodular morphology have been dubbed 'Nebula Stone' and sold as a lapidary product under this trade name. There is an interesting description and some reported identification efforts at: www.rockhounds.com/rockgem/articles/nebula.shtml
I thank Cran Cowan and Radostin Pavlov for helping with this puzzle.