Unusually vivid tourmalines from the state of Paraiba, in north eastern Brazil, have attracted great interest since they first appeared on the international gem market in 1989. This article describes what is known of the locality at this time, but focuses on the most striking characteristic of the se gem tourmalines: the unusual colors in which they occur. Quantitative chemical analyses revealed that these elbaite tourmalines contain surprisingly high concentrations of copper, up to 1.92. wt. % Cu (or 2.38 wt. % CuO). Their colors are due to Cu 2 + or a combination of Cu 2 + , Mn 3 + , and other causes. Some colors can be produced by heat treatment, but most also occur naturally.
Unusually vivid tourmalines from the state of Paraiba, in north eastern Brazil, have attracted great interest since they first appeared on the international gem market in 1989. This article describes what is known of the locality at this time, but focuses on the most striking characteristic of the se gem tourmalines: the unusual colors in which they occur. Quantitative chemical analyses revealed that these elbaite tourmalines contain surprisingly high concentrations of copper, up to 1.92. wt. % Cu (or 2.38 wt. % CuO). Their colors are due to Cu 2 + or a combination of Cu 2 + , Mn 3 + , and other causes. Some colors can be produced by heat treatment, but most also occur naturally.