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.
Solution-Generated Pink Colour Surrounding Growth Tubes and Cracks in Blue to Blue-Green Copper-Bearing Tourmalines from Mozambique
Several transparent, faceted, blue to blue-green copper-bearing tourmalines containing growth tubes and cracks surrounded by sleeves of pink colour were examined for this report.
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.
An Update on “Paraíba” Tourmaline from Brazil
“Paraíba” tourmalines continue to be recovered in small amounts from north-eastern Brazil.
Pleochroism in Faceted Gems: An Introduction
Describes the phenomenon of pleochroism and its complex effect on the appearance of coloured stones.
Interesting Red Tourmaline from Zambia
A new source of red tourmaline is identified in Zambia.