Pleochroism in Faceted Gems: An Introduction
Describes the phenomenon of pleochroism and its complex effect on the appearance of coloured stones.
Multicoloured Bismuth-bearing Tourmaline from Lundazi, Zambia
Tourmalines from an alluvial deposit near Lundazi in Zambia consist of colour-zoned pink/colourless/yellow-green “watermelon” nodules.
Spectral Differentiation Between Copper and Iron Colourants in Gem Tourmalines
The authors used Vis-NIR spectral measurements combined with LA-ICP-MS data to investigate the usefulness of absorption spectra.